diff --git a/app/src/main/java/com/doyoonkim/knutice/AppNavHost.kt b/app/src/main/java/com/doyoonkim/knutice/AppNavHost.kt
index e7fddc08..0c3f28dc 100644
--- a/app/src/main/java/com/doyoonkim/knutice/AppNavHost.kt
+++ b/app/src/main/java/com/doyoonkim/knutice/AppNavHost.kt
@@ -17,7 +17,8 @@ fun AppNavHost(
     modifier: Modifier = Modifier,
     contentPadding: PaddingValues,
     navController: NavHostController,
-    viewModelFactory: ViewModelProvider.Factory
+    viewModelFactory: ViewModelProvider.Factory,
+    onExit: () -> Unit = { /* ON EXIT HANDLING */ }
 ) {
     NavHost(
         modifier = modifier.padding(
@@ -38,7 +39,8 @@ fun AppNavHost(
             },
             onBookmarkServiceRequested = {
                 navController.navigate("bookmark/${it.noticeId}/${it.noticeTitle}/${it.noticeInfo}")
-            }
+            },
+            onExit = onExit
         )
 
         bookmarkServiceGraph(
@@ -47,7 +49,8 @@ fun AppNavHost(
             contentPadding = contentPadding,
             onNoticeDetailRequested = { target ->
                 navController.navigate("noticeDetail/${target.nttId}/${Uri.encode(target.contentUrl)}/${target.isFabVisible}")
-            }
+            },
+            onExit = onExit
         )
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/doyoonkim/knutice/MainActivity.kt b/app/src/main/java/com/doyoonkim/knutice/MainActivity.kt
index d14956ea..29b2c898 100644
--- a/app/src/main/java/com/doyoonkim/knutice/MainActivity.kt
+++ b/app/src/main/java/com/doyoonkim/knutice/MainActivity.kt
@@ -22,7 +22,6 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.systemBarsPadding
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.shape.RoundedCornerShape
@@ -67,6 +66,7 @@ import com.doyoonkim.common.theme.title
 import com.doyoonkim.common.ui.PermissionRationaleComposable
 import com.doyoonkim.common.R
 import com.doyoonkim.notification.local.NotificationAlarmScheduler
+import kotlinx.coroutines.delay
 import javax.inject.Inject
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -121,6 +121,7 @@ class MainActivity : ComponentActivity() {
                 }
 
                 LaunchedEffect(Unit) {
+                    delay(200L)     // Reduce workload on MainThread on its first initialization.
                     // Permission check
                     requestPermissionLauncher.launch(
                         arrayOf(
@@ -216,13 +217,7 @@ class MainActivity : ComponentActivity() {
                                         enabled = true,
                                         onClick = {
                                             if (!bottomBarState.second) {
-                                                navController.navigate(NavRoutes.Home.route) {
-                                                    popUpTo(navController.graph.startDestinationId) {
-                                                        saveState = true
-                                                    }
-                                                    launchSingleTop = true
-                                                    restoreState = true
-                                                }
+                                                navController.navigate(NavRoutes.Home.route)
                                             }
                                         },
                                         icon = {
@@ -243,13 +238,7 @@ class MainActivity : ComponentActivity() {
                                         enabled = true,
                                         onClick = {
                                             if (!bottomBarState.third) {
-                                                navController.navigate(NavRoutes.Bookmark.route) {
-                                                    popUpTo(navController.graph.startDestinationId) {
-                                                        saveState = true
-                                                    }
-                                                    launchSingleTop = true
-                                                    restoreState = true
-                                                }
+                                                navController.navigate(NavRoutes.Bookmark.route)
                                             }
                                         },
                                         icon = {
@@ -276,7 +265,8 @@ class MainActivity : ComponentActivity() {
                         modifier = Modifier,
                         contentPadding = contentPadding,
                         navController = navController,
-                        viewModelFactory = viewModelFactory
+                        viewModelFactory = viewModelFactory,
+                        onExit = { activity.finish() }
                     )
 
                     LaunchedEffect(Unit) {
diff --git a/app/src/main/java/com/doyoonkim/knutice/MainApplication.kt b/app/src/main/java/com/doyoonkim/knutice/MainApplication.kt
index 91ee85de..4a493659 100644
--- a/app/src/main/java/com/doyoonkim/knutice/MainApplication.kt
+++ b/app/src/main/java/com/doyoonkim/knutice/MainApplication.kt
@@ -11,6 +11,7 @@ import com.doyoonkim.knutice.di.AppComponent
 import com.doyoonkim.knutice.di.DaggerAppComponent
 import com.doyoonkim.notification.fcm.PushNotificationService
 import com.doyoonkim.notification.fcm.TokenHandler
+import kotlinx.coroutines.coroutineScope
 import javax.inject.Inject
 
 class MainApplication() : Application(), AppInjectorProvider {
diff --git a/core/data/src/main/java/com/doyoonkim/data/repository/RemoteRepositoryImpl.kt b/core/data/src/main/java/com/doyoonkim/data/repository/RemoteRepositoryImpl.kt
index c7384868..f3a5bf2a 100644
--- a/core/data/src/main/java/com/doyoonkim/data/repository/RemoteRepositoryImpl.kt
+++ b/core/data/src/main/java/com/doyoonkim/data/repository/RemoteRepositoryImpl.kt
@@ -10,7 +10,9 @@ import com.doyoonkim.network.KnuticeRemoteSource
 import com.doyoonkim.network.model.DeviceTokenRequest
 import com.doyoonkim.network.model.TopicSubscriptionPreferencesRequest
 import com.doyoonkim.network.model.UserReportRequest
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
 import model.NetworkResult
 import javax.inject.Inject
 
@@ -30,7 +32,7 @@ class RemoteRepositoryImpl @Inject constructor(
                 emit(null)
             }
         )
-    }
+    }.flowOn(Dispatchers.IO)
 
     override fun queryNoticesPerPage(category: NoticeCategory, lastNttId: Int?) = flow {
         remoteSource.getNoticesPerPage(category, lastNttId).fold(
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchAllBookmarks.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchAllBookmarks.kt
index 730e6656..8b7b5c8c 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchAllBookmarks.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchAllBookmarks.kt
@@ -4,6 +4,7 @@ import com.doyoonkim.domain.LocalRepository
 import com.doyoonkim.model.BookmarkVO
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.emitAll
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
@@ -24,6 +25,8 @@ class FetchAllBookmarksImpl @Inject constructor(
                     nullable?.let { vo-> emit(Pair(bookmarkVO, vo)) }
                 })
             }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeById.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeById.kt
index 39173253..0bc4082e 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeById.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeById.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -17,5 +18,7 @@ class FetchNoticeByIdImpl @Inject constructor(
     override operator fun invoke(nttId: Int) =
         remoteRepository.queryNoticeById(nttId).transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeByIdFromLocal.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeByIdFromLocal.kt
index cb9a1998..ee915900 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeByIdFromLocal.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticeByIdFromLocal.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.LocalRepository
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -17,6 +18,8 @@ class FetchNoticeByIdFromLocalImpl @Inject constructor(
     override operator fun invoke(nttId: Int) =
         localRepository.queryNoticeById(nttId).transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesByKeyword.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesByKeyword.kt
index 8f9b36bb..ed05938f 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesByKeyword.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesByKeyword.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -17,5 +18,7 @@ class FetchNoticesByKeywordImpl @Inject constructor(
     override operator fun invoke(keyword: String) =
         remoteRepository.queryNoticesByKeyword(keyword).transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesPerPage.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesPerPage.kt
index 511683c2..b81102ce 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesPerPage.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchNoticesPerPage.kt
@@ -4,6 +4,7 @@ import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.NoticeCategory
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -21,5 +22,7 @@ class FetchNoticesPerPageImpl @Inject constructor(
             else queryNoticesPerPage(category, lastNttId)
         }.transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopThreeNotices.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopThreeNotices.kt
index 696d6ab0..22231f2b 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopThreeNotices.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopThreeNotices.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.TopThreeNoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -17,6 +18,8 @@ class FetchTopThreeNoticesImpl @Inject constructor(
     override operator fun invoke(): Flow<TopThreeNoticeVO> =
         remoteRepository.queryTopThreeNotices().transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopicSubscriptionStatus.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopicSubscriptionStatus.kt
index 8f226ddd..9021ae7b 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopicSubscriptionStatus.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/FetchTopicSubscriptionStatus.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.TopicSubscriptionPreferencesVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
 
@@ -17,6 +18,8 @@ class FetchTopicSubscriptionStatusImpl @Inject constructor(
     override operator fun invoke() =
         remoteRepository.queryTopicSubscriptionStatus().transform { nullable ->
             nullable?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/ModifyBookmark.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/ModifyBookmark.kt
index 37089257..0c45f607 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/ModifyBookmark.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/ModifyBookmark.kt
@@ -5,6 +5,7 @@ import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.BookmarkVO
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.emitAll
 import kotlinx.coroutines.flow.transform
 import javax.inject.Inject
@@ -26,6 +27,8 @@ class ModifyBookmarkImpl @Inject constructor(
     override fun query(nttId: Int): Flow<BookmarkVO> =
         localRepository.queryBookmarkByNttId(nttId).transform { result ->
             result?.let { emit(it) }
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
     // TODO: Need to be revised later. (Is NoticeVO really required)
@@ -35,9 +38,14 @@ class ModifyBookmarkImpl @Inject constructor(
             remoteRepository.queryNoticeById(bookmark.targetNoticeNttId).transform { result ->
                 if (result != null) emitAll(localRepository.createBookmark(bookmark, result))
                 else emit(false)
+            }.catch {
+                /* Internal Error. Consume values, and never emit values. */
             }
         } else {
             localRepository.updateBookmark(bookmark)
+                .catch {
+                    /* Internal Error. Consume values, and never emit values. */
+                }
         }
     }
 
@@ -45,6 +53,8 @@ class ModifyBookmarkImpl @Inject constructor(
         localRepository.requestBookmarkDeletion(bookmark).transform { result ->
             if (result) emitAll(localRepository.requestNoticeDeletion(notice))
             else emit(false)
+        }.catch {
+            /* Internal Error. Consume values, and never emit values. */
         }
 
 }
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitNotificationPreferences.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitNotificationPreferences.kt
index 1d891f3e..cc040342 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitNotificationPreferences.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitNotificationPreferences.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.requestBody.TopicSubscriptionPreferencesBody
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import javax.inject.Inject
 
 interface SubmitNotificationPreferences {
@@ -15,4 +16,7 @@ class SubmitNotificationPreferencesImpl @Inject constructor(
 
     override operator fun invoke(body: TopicSubscriptionPreferencesBody) =
         remoteRepository.requestTopicSubscriptionPreferencesSubmission(body)
+            .catch {
+                /* Internal Error. Consume values, and never emit values. */
+            }
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitUserReport.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitUserReport.kt
index 6099c0f8..48f955f2 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitUserReport.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/SubmitUserReport.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.requestBody.UserReportBody
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import javax.inject.Inject
 
 interface SubmitUserReport {
@@ -15,5 +16,8 @@ class SubmitUserReportImpl @Inject constructor(
 
     override operator fun invoke(body: UserReportBody) =
         remoteRepository.requestUserReportSubmission(body)
+            .catch {
+                /* Internal Error. Consume values, and never emit values. */
+            }
 
 }
\ No newline at end of file
diff --git a/core/domain/src/main/java/com/doyoonkim/domain/usecases/ValidateDeviceToken.kt b/core/domain/src/main/java/com/doyoonkim/domain/usecases/ValidateDeviceToken.kt
index 3c9f694c..993be486 100644
--- a/core/domain/src/main/java/com/doyoonkim/domain/usecases/ValidateDeviceToken.kt
+++ b/core/domain/src/main/java/com/doyoonkim/domain/usecases/ValidateDeviceToken.kt
@@ -3,6 +3,7 @@ package com.doyoonkim.domain.usecases
 import com.doyoonkim.domain.RemoteRepository
 import com.doyoonkim.model.requestBody.DeviceTokenBody
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
 import javax.inject.Inject
 
 
@@ -16,4 +17,8 @@ class ValidateDeviceTokenImpl @Inject constructor(
 
     override operator fun invoke(requestBody: DeviceTokenBody) =
         remoteRepository.requestTokenValidation(requestBody)
+            .catch {
+                /* Internal Error. Consume values, and never emit values. */
+                emit(false)
+            }
 }
\ No newline at end of file
diff --git a/core/notification/src/main/java/com/doyoonkim/notification/fcm/TokenHandler.kt b/core/notification/src/main/java/com/doyoonkim/notification/fcm/TokenHandler.kt
index 7d3f119b..b9052946 100644
--- a/core/notification/src/main/java/com/doyoonkim/notification/fcm/TokenHandler.kt
+++ b/core/notification/src/main/java/com/doyoonkim/notification/fcm/TokenHandler.kt
@@ -7,7 +7,10 @@ import com.google.android.gms.tasks.OnCompleteListener
 import com.google.firebase.messaging.FirebaseMessaging
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
@@ -17,26 +20,32 @@ class TokenHandler @Inject constructor(
     private val TAG = this.javaClass.name
 
     fun handleCurrentTokenRequest() {
-        FirebaseMessaging.getInstance().token.addOnCompleteListener(OnCompleteListener { task ->
-            if (!task.isSuccessful) {
-                Log.d(TAG, "Incomplete task: ${task.exception}")
-                return@OnCompleteListener
-            }
+        val completeMarker = Job()
+        CoroutineScope(Dispatchers.IO + completeMarker).launch {
+            FirebaseMessaging.getInstance().token.addOnCompleteListener(OnCompleteListener { task ->
+                if (!task.isSuccessful) {
+                    Log.d(TAG, "Incomplete task: ${task.exception}")
+                    return@OnCompleteListener
+                }
 
-            // Get new FCM registration token
-            val registrationToken = task.result
-            Log.d(TAG, "Received Token: $registrationToken")
+                // Get new FCM registration token
+                val registrationToken = task.result
+                Log.d(TAG, "Received Token: $registrationToken")
 
-            // POST request to upload current token to the web server.
-            CoroutineScope(Dispatchers.IO).launch {
-                Log.d(TAG, "Start validating Token")
-                validateDeviceToken(
-                    DeviceTokenBody(fcmToken = registrationToken)
-                ).collectLatest { result ->
-                    if (result) Log.d(TAG, "Validation Successful")
-                    else Log.d(TAG, "Unable to validate")
+                // POST request to upload current token to the web server.
+                CoroutineScope(Dispatchers.IO).launch {
+                    Log.d(TAG, "Start validating Token")
+                    validateDeviceToken(DeviceTokenBody(fcmToken = registrationToken))
+                        .flowOn(Dispatchers.IO)
+                        .collectLatest { result ->
+                            if (result) Log.d(TAG, "Validation Successful")
+                            else Log.d(TAG, "Unable to validate")
+                        }
+                    completeMarker.complete()
                 }
-            }
-        })
+            })
+            delay(5000L)
+            if (!completeMarker.isCompleted) completeMarker.complete()
+        }
     }
 }
\ No newline at end of file
diff --git a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/bookmarkServiceGraph.kt b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/bookmarkServiceGraph.kt
index 8ddbfcbd..82b435a3 100644
--- a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/bookmarkServiceGraph.kt
+++ b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/bookmarkServiceGraph.kt
@@ -22,7 +22,8 @@ fun NavGraphBuilder.bookmarkServiceGraph(
     navController: NavController,
     viewModelFactory: ViewModelProvider.Factory,
     contentPadding: PaddingValues,
-    onNoticeDetailRequested: (NoticeDetail) -> Unit
+    onNoticeDetailRequested: (NoticeDetail) -> Unit,
+    onExit: () -> Unit = {  }
 ) {
 
     composable(NavRoutes.Bookmark.route) {
@@ -33,7 +34,9 @@ fun NavGraphBuilder.bookmarkServiceGraph(
             onBookmarkSelected = {
                 navController.navigate("bookmark/${it.noticeId}/${it.noticeTitle}/${it.noticeInfo}")
             },
-            onBackPressed = { navController.popBackStack() }
+            onBackPressed = {
+                navController.popBackStack().also { if (!it) onExit() }
+            }
         )
     }
 
diff --git a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/list/BookmarkListScreen.kt b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/list/BookmarkListScreen.kt
index e3884eef..529b8b87 100644
--- a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/list/BookmarkListScreen.kt
+++ b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/list/BookmarkListScreen.kt
@@ -35,6 +35,7 @@ import com.doyoonkim.common.theme.containerBackgroundSolid
 import com.doyoonkim.common.R
 import com.doyoonkim.common.theme.subTitle
 import com.doyoonkim.common.ui.NotificationPreviewCardMarked
+import kotlinx.coroutines.delay
 
 @Composable
 fun BookmarkListScreen(
diff --git a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/viewmodel/BookmarkListViewModel.kt b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/viewmodel/BookmarkListViewModel.kt
index fb17f337..f7651166 100644
--- a/feature/bookmark/src/main/java/com/doyoonkim/bookmark/viewmodel/BookmarkListViewModel.kt
+++ b/feature/bookmark/src/main/java/com/doyoonkim/bookmark/viewmodel/BookmarkListViewModel.kt
@@ -7,6 +7,7 @@ import com.doyoonkim.domain.usecases.FetchAllBookmarks
 import com.doyoonkim.model.BookmarkVO
 import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.collectLatest
@@ -23,8 +24,8 @@ class BookmarkListViewModel @Inject constructor(
     val uiState = _uiState.asStateFlow()
 
     fun getAllBookmarks() {
-        updateFetchingStatus(false)
         viewModelScope.launch {
+            updateFetchingStatus(false).also { delay(200L) }
             fetchAllBookmarks()
                 .flowOn(Dispatchers.IO)
                 .collectLatest { result ->
diff --git a/feature/main/src/main/java/com/doyoonkim/main/MainServiceNavGraph.kt b/feature/main/src/main/java/com/doyoonkim/main/MainServiceNavGraph.kt
index 5b5decb6..63dd317a 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/MainServiceNavGraph.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/MainServiceNavGraph.kt
@@ -38,7 +38,8 @@ fun NavGraphBuilder.mainServiceNavGraph(
     viewModelFactory: ViewModelProvider.Factory,
     contentPadding: PaddingValues,
     onNoticeDetailRequested: (NoticeDetail) -> Unit,
-    onBookmarkServiceRequested: (BookmarkInfo) -> Unit
+    onBookmarkServiceRequested: (BookmarkInfo) -> Unit,
+    onExit: () -> Unit = {  }
 ) {
     // ViewModels will be injected via ViewModelFactory
     composable(NavRoutes.Home.route) {
@@ -46,7 +47,9 @@ fun NavGraphBuilder.mainServiceNavGraph(
             modifier = Modifier.padding(5.dp),
             viewModel = viewModel<HomeViewModel>(factory = viewModelFactory),
             bottomPadding = contentPadding.calculateBottomPadding(),
-            onGoBackAction = { navController.popBackStack() },
+            onGoBackAction = {
+                navController.popBackStack().also { if (!it) onExit() }
+            },
             onMoreNoticeRequested = { dest ->
                 navController.run {
                     when(dest) {
diff --git a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeDetailScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeDetailScreen.kt
index a821da9d..6462a867 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeDetailScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeDetailScreen.kt
@@ -65,6 +65,7 @@ fun NoticeDetailScreen(
     if (noticeInfo.second.isNotBlank()) {
         Box(
             modifier = modifier
+                .windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom))
         ) {
             AndroidView(
                 modifier = Modifier.fillMaxSize(),
diff --git a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeSearchScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeSearchScreen.kt
index 0dac7b72..cc423a90 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeSearchScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticeSearchScreen.kt
@@ -9,9 +9,14 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.WindowInsetsSides
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.only
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.systemBars
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.lazy.LazyColumn
@@ -59,6 +64,7 @@ fun NoticeSearchScreen(
         modifier = modifier
             .fillMaxWidth()
             .wrapContentHeight()
+            .windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom))
     ) {
         Row(
             modifier = Modifier
diff --git a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticesInCategoryScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticesInCategoryScreen.kt
index 20c10a69..e3d41858 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/notice/NoticesInCategoryScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/notice/NoticesInCategoryScreen.kt
@@ -6,8 +6,13 @@ import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.WindowInsetsSides
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.only
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.systemBars
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.lazy.LazyColumn
@@ -61,6 +66,7 @@ fun NoticesInCategoryScreen(
     Box(
         modifier = modifier.fillMaxWidth()
             .background(MaterialTheme.colorScheme.containerBackground)
+            .windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom))
             .pullRefresh(pullRefreshState)
     ) {
         LazyColumn(
diff --git a/feature/main/src/main/java/com/doyoonkim/main/preference/NotificationPreferencesScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/preference/NotificationPreferencesScreen.kt
index cd52c3a4..a4673104 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/preference/NotificationPreferencesScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/preference/NotificationPreferencesScreen.kt
@@ -7,17 +7,24 @@ import android.content.Context.NOTIFICATION_SERVICE
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.graphics.Paint.Align
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.WindowInsetsSides
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.only
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.systemBars
 import androidx.compose.foundation.layout.systemBarsPadding
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.layout.wrapContentWidth
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Text
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.MaterialTheme
@@ -72,122 +79,135 @@ fun NotificationPreferencesScreen(
         )
     }
 
-    Column(
-        modifier = modifier.fillMaxSize(),
-        horizontalAlignment = Alignment.CenterHorizontally,
-        verticalArrangement = Arrangement.Top
+    Box(
+        modifier = Modifier
+            .fillMaxSize()
+            .windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom))
     ) {
-        Text(
-            modifier = Modifier.fillMaxWidth().wrapContentHeight(),
-            text = stringResource(R.string.pref_notification_title),
-            color = MaterialTheme.colorScheme.title,
-            fontWeight = FontWeight.SemiBold,
-            fontSize = 14.sp,
-            textAlign = TextAlign.Start
-        )
-
-        HorizontalDivider(
-            Modifier.fillMaxWidth(),
-            color = MaterialTheme.colorScheme.subTitle
-        )
-
         Column(
-            modifier = Modifier.wrapContentHeight()
-                .padding(top = 15.dp, bottom = 15.dp),
+            modifier = modifier.fillMaxSize(),
             horizontalAlignment = Alignment.CenterHorizontally,
             verticalArrangement = Arrangement.Top
         ) {
-            Row(
-                verticalAlignment = Alignment.CenterVertically
+            Text(
+                modifier = Modifier.fillMaxWidth().wrapContentHeight(),
+                text = stringResource(R.string.pref_notification_title),
+                color = MaterialTheme.colorScheme.title,
+                fontWeight = FontWeight.SemiBold,
+                fontSize = 14.sp,
+                textAlign = TextAlign.Start
+            )
+
+            HorizontalDivider(
+                Modifier.fillMaxWidth(),
+                color = MaterialTheme.colorScheme.subTitle
+            )
+
+            Column(
+                modifier = Modifier.wrapContentHeight()
+                    .padding(top = 15.dp, bottom = 15.dp),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.Top
             ) {
-                Column(
-                    modifier = Modifier.wrapContentHeight().weight(5f),
-                    verticalArrangement = Arrangement.spacedBy(5.dp)
+                Row(
+                    verticalAlignment = Alignment.CenterVertically
                 ) {
-                    Text(
-                        modifier = Modifier.fillMaxWidth().wrapContentHeight(),
-                        text = stringResource(R.string.enable_notification_title),
-                        color = MaterialTheme.colorScheme.title,
-                        fontWeight = FontWeight.Medium,
-                        fontSize = 18.sp,
-                        textAlign = TextAlign.Start
-                    )
-
-                    Text(
-                        modifier = Modifier.fillMaxWidth().wrapContentHeight(),
-                        text = stringResource(R.string.enable_service_notification_sub),
-                        color = MaterialTheme.colorScheme.subTitle,
-                        fontWeight = FontWeight.Normal,
-                        fontSize = 12.sp,
-                        textAlign = TextAlign.Start
+                    Column(
+                        modifier = Modifier.wrapContentHeight().weight(5f),
+                        verticalArrangement = Arrangement.spacedBy(5.dp)
+                    ) {
+                        Text(
+                            modifier = Modifier.fillMaxWidth().wrapContentHeight(),
+                            text = stringResource(R.string.enable_notification_title),
+                            color = MaterialTheme.colorScheme.title,
+                            fontWeight = FontWeight.Medium,
+                            fontSize = 18.sp,
+                            textAlign = TextAlign.Start
+                        )
+
+                        Text(
+                            modifier = Modifier.fillMaxWidth().wrapContentHeight(),
+                            text = stringResource(R.string.enable_service_notification_sub),
+                            color = MaterialTheme.colorScheme.subTitle,
+                            fontWeight = FontWeight.Normal,
+                            fontSize = 12.sp,
+                            textAlign = TextAlign.Start
+                        )
+                    }
+
+                    Switch(
+                        checked = uiStatus.isMainNotificationPermissionGranted,
+                        colors = SwitchDefaults.colors().copy(
+                            checkedTrackColor = MaterialTheme.colorScheme.buttonPurple,
+                            checkedThumbColor = Color.White
+                        ),
+                        onCheckedChange = {
+                            val settingIntent = Intent(
+                                "android.settings.APP_NOTIFICATION_SETTINGS"
+                            ).apply {
+                                this.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                                this.putExtra(
+                                    "android.provider.extra.APP_PACKAGE",
+                                    context.packageName
+                                )
+                            }
+                            context.startActivity(settingIntent)
+                        },
+                        enabled = true
                     )
                 }
+            }
 
-                Switch(
-                    checked = uiStatus.isMainNotificationPermissionGranted,
-                    colors = SwitchDefaults.colors().copy(
-                        checkedTrackColor = MaterialTheme.colorScheme.buttonPurple,
-                        checkedThumbColor = Color.White
-                    ),
-                    onCheckedChange = {
-                        val settingIntent = Intent(
-                            "android.settings.APP_NOTIFICATION_SETTINGS"
-                        ).apply {
-                            this.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
-                            this.putExtra(
-                                "android.provider.extra.APP_PACKAGE",
-                                context.packageName
-                            )
-                        }
-                        context.startActivity(settingIntent)
-                    },
-                    enabled = true
-                )
+            LabeledToggleSwitch(
+                modifier = Modifier.padding(start = 10.dp),
+                titleText = stringResource(R.string.general_notificaiton_channel_name),
+                subTitleText = stringResource(R.string.general_notification_channel_description),
+                isChecked = uiStatus.isEachChannelAllowed[0],
+                isEnabled = uiStatus.isMainNotificationPermissionGranted && uiStatus.isSyncCompleted
+            ) {
+                viewModel.updateChannelPreferenceState(0, it)
             }
-        }
 
-        LabeledToggleSwitch(
-            modifier = Modifier.padding(start = 10.dp),
-            titleText = stringResource(R.string.general_notificaiton_channel_name),
-            subTitleText = stringResource(R.string.general_notification_channel_description),
-            isChecked = uiStatus.isEachChannelAllowed[0],
-            isEnabled = uiStatus.isMainNotificationPermissionGranted
-        ) {
-            viewModel.updateChannelPreferenceState(0, it)
-        }
+            LabeledToggleSwitch(
+                modifier = Modifier.padding(start = 10.dp),
+                titleText = stringResource(R.string.academic_notification_channel_name),
+                subTitleText = stringResource(R.string.academic_notification_channel_description),
+                isChecked = uiStatus.isEachChannelAllowed[1],
+                isEnabled = uiStatus.isMainNotificationPermissionGranted && uiStatus.isSyncCompleted
+            ) {
+                viewModel.updateChannelPreferenceState(1, it)
+            }
 
-        LabeledToggleSwitch(
-            modifier = Modifier.padding(start = 10.dp),
-            titleText = stringResource(R.string.academic_notification_channel_name),
-            subTitleText = stringResource(R.string.academic_notification_channel_description),
-            isChecked = uiStatus.isEachChannelAllowed[1],
-            isEnabled = uiStatus.isMainNotificationPermissionGranted
-        ) {
-            viewModel.updateChannelPreferenceState(1, it)
-        }
+            LabeledToggleSwitch(
+                modifier = Modifier.padding(start = 10.dp),
+                titleText = stringResource(R.string.scholarship_notification_channel_name),
+                subTitleText = stringResource(R.string.scholarship_notification_channel_description),
+                isChecked = uiStatus.isEachChannelAllowed[2],
+                isEnabled = uiStatus.isMainNotificationPermissionGranted && uiStatus.isSyncCompleted
+            ) {
+                viewModel.updateChannelPreferenceState(2, it)
+            }
 
-        LabeledToggleSwitch(
-            modifier = Modifier.padding(start = 10.dp),
-            titleText = stringResource(R.string.scholarship_notification_channel_name),
-            subTitleText = stringResource(R.string.scholarship_notification_channel_description),
-            isChecked = uiStatus.isEachChannelAllowed[2],
-            isEnabled = uiStatus.isMainNotificationPermissionGranted
-        ) {
-            viewModel.updateChannelPreferenceState(2, it)
+            LabeledToggleSwitch(
+                modifier = Modifier.padding(start = 10.dp),
+                titleText = stringResource(R.string.event_notification_channel_name),
+                subTitleText = stringResource(R.string.event_notification_channel_description),
+                isChecked = uiStatus.isEachChannelAllowed[3],
+                isEnabled = uiStatus.isMainNotificationPermissionGranted && uiStatus.isSyncCompleted
+            ) {
+                viewModel.updateChannelPreferenceState(3, it)
+            }
         }
 
-        LabeledToggleSwitch(
-            modifier = Modifier.padding(start = 10.dp),
-            titleText = stringResource(R.string.event_notification_channel_name),
-            subTitleText = stringResource(R.string.event_notification_channel_description),
-            isChecked = uiStatus.isEachChannelAllowed[3],
-            isEnabled = uiStatus.isMainNotificationPermissionGranted
-        ) {
-            viewModel.updateChannelPreferenceState(3, it)
+        if (!uiStatus.isSyncCompleted) {
+            Box(
+                modifier = Modifier.matchParentSize()
+                    .background(Color.Gray.copy(alpha = 0.5f))
+            ) {
+                CircularProgressIndicator(modifier = Modifier.align(Alignment.Center))
+            }
         }
-
     }
-
 }
 
 fun isMainNotificationPermissionGranted(
diff --git a/feature/main/src/main/java/com/doyoonkim/main/preference/OssNoticeScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/preference/OssNoticeScreen.kt
index 3f923c8d..ddcf9867 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/preference/OssNoticeScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/preference/OssNoticeScreen.kt
@@ -2,6 +2,11 @@ package com.doyoonkim.main.preference
 
 import android.webkit.WebView
 import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.WindowInsetsSides
+import androidx.compose.foundation.layout.only
+import androidx.compose.foundation.layout.systemBars
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.viewinterop.AndroidView
@@ -14,7 +19,7 @@ fun OssNoticeScreen(
     BackHandler { onBackPressed() }
 
     AndroidView(
-        modifier = modifier,
+        modifier = modifier.windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom)),
         factory = { context ->
             WebView(context).apply {
                 loadUrl("https://knutice.github.io/KNUTICE-OpenSourceLicense/Android/opensource.html")
diff --git a/feature/main/src/main/java/com/doyoonkim/main/preference/UserPreferencesScreen.kt b/feature/main/src/main/java/com/doyoonkim/main/preference/UserPreferencesScreen.kt
index 68ace30c..b74e8cce 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/preference/UserPreferencesScreen.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/preference/UserPreferencesScreen.kt
@@ -5,8 +5,13 @@ import androidx.compose.foundation.Image
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.WindowInsets
+import androidx.compose.foundation.layout.WindowInsetsSides
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.only
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.systemBars
+import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.wrapContentHeight
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.material3.HorizontalDivider
@@ -40,7 +45,8 @@ fun UserPreferenceScreen(
     BackHandler { onBackPressed() }
 
     Column(
-        modifier = modifier,
+        modifier = modifier
+            .windowInsetsPadding(WindowInsets.systemBars.only(WindowInsetsSides.Bottom)),
         horizontalAlignment = Alignment.CenterHorizontally,
         verticalArrangement = Arrangement.Top
     ) {
diff --git a/feature/main/src/main/java/com/doyoonkim/main/viewmodel/HomeViewModel.kt b/feature/main/src/main/java/com/doyoonkim/main/viewmodel/HomeViewModel.kt
index 689dae5f..21cdf08e 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/viewmodel/HomeViewModel.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/viewmodel/HomeViewModel.kt
@@ -1,5 +1,6 @@
 package com.doyoonkim.main.viewmodel
 
+import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.doyoonkim.domain.usecases.FetchTopThreeNoticesImpl
@@ -7,6 +8,7 @@ import com.doyoonkim.model.NoticeVO
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.update
diff --git a/feature/main/src/main/java/com/doyoonkim/main/viewmodel/NotificationPreferencesViewModel.kt b/feature/main/src/main/java/com/doyoonkim/main/viewmodel/NotificationPreferencesViewModel.kt
index 8e8e9501..0eea812b 100644
--- a/feature/main/src/main/java/com/doyoonkim/main/viewmodel/NotificationPreferencesViewModel.kt
+++ b/feature/main/src/main/java/com/doyoonkim/main/viewmodel/NotificationPreferencesViewModel.kt
@@ -1,5 +1,6 @@
 package com.doyoonkim.main.viewmodel
 
+import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.doyoonkim.domain.usecases.FetchTopicSubscriptionStatusImpl
@@ -16,6 +17,7 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withTimeout
 import javax.inject.Inject
 
 class NotificationPreferencesViewModel @Inject constructor(
@@ -43,7 +45,7 @@ class NotificationPreferencesViewModel @Inject constructor(
     fun updateChannelPreferenceState(index: Int, state: Boolean) {
         _uiState.update {
             it.copy(
-                isEachChannelAllowed = it.isEachChannelAllowed.updateValueByIndex(index, state)
+                isSyncCompleted = false
             )
         }
 
@@ -59,10 +61,18 @@ class NotificationPreferencesViewModel @Inject constructor(
                     if (!result) {
                         _uiState.update {
                             it.copy(
-                                isEachChannelAllowed = it.isEachChannelAllowed.updateValueByIndex(index, !state),
+                                isSyncCompleted = true,
                                 isError = true
                             )
                         }
+                    } else {
+                        _uiState.update {
+                            it.copy(
+                                isEachChannelAllowed = it.isEachChannelAllowed.updateValueByIndex(index, state),
+                                isSyncCompleted = true,
+                                isError = false
+                            )
+                        }
                     }
                 }
             }
@@ -73,20 +83,33 @@ class NotificationPreferencesViewModel @Inject constructor(
 
     fun getTopicSubscriptionStatus() =
         viewModelScope.launch {
-            fetchTopicSubscriptionStatus()
-                .flowOn(Dispatchers.IO)
-                .collectLatest { status ->
-                    _uiState.update {
-                        it.copy(
-                            isEachChannelAllowed = listOf(
-                                status.general,
-                                status.academic,
-                                status.scholarship,
-                                status.event
+            withTimeout(5000L) {
+                fetchTopicSubscriptionStatus()
+                    .flowOn(Dispatchers.IO)
+                    .collectLatest { status ->
+                        _uiState.update {
+                            it.copy(
+                                isEachChannelAllowed = listOf(
+                                    status.general,
+                                    status.academic,
+                                    status.scholarship,
+                                    status.event
+                                ),
+                                isSyncCompleted = true,
+                                isError = false
                             )
-                        )
+                        }
                     }
+            }.runCatching {
+                /* DO NOTHING (SYNC COMPLETED ON TIME. */
+            }.onFailure {
+                _uiState.update {
+                    it.copy(
+                        isSyncCompleted = true,
+                        isError = true
+                    )
                 }
+            }
         }
 
     private fun List<Boolean>.updateValueByIndex(index: Int, value: Boolean) =