diff --git a/server.ts b/server.ts
index 546c0df..b93e574 100644
--- a/server.ts
+++ b/server.ts
@@ -36,10 +36,6 @@ type Handler = { default: { fetch: (req: Request) => Promise<Response> } };
 
 const { default: handler } = (await import(SERVER_ENTRY.href)) as Handler;
 
-if (!process.env.ADMIN_PANEL_METRICS_SECRET) {
-  console.warn('[metrics] ADMIN_PANEL_METRICS_SECRET is not set — /metrics will return 401 for all requests');
-}
-
 async function buildStaticRoutes(): Promise<Record<string, () => Response>> {
   const routes: Record<string, () => Response> = {};
   for await (const path of new Glob('**/*').scan(CLIENT_DIR)) {
@@ -51,7 +47,7 @@ async function buildStaticRoutes(): Promise<Record<string, () => Response>> {
   return routes;
 }
 
-Bun.serve({
+const server = Bun.serve({
   port: Number(process.env.PORT ?? 3000),
   routes: {
     ...(await buildStaticRoutes()),
@@ -72,4 +68,8 @@ Bun.serve({
   },
 });
 
-console.log(`Admin panel listening on http://localhost:${process.env.PORT ?? 3000}`);
+console.log(`Admin panel listening on http://localhost:${server.port}`);
+
+if (!process.env.ADMIN_PANEL_METRICS_SECRET) {
+  console.warn('[metrics] ADMIN_PANEL_METRICS_SECRET is not set — /metrics will return 401 for all requests');
+}
diff --git a/src/server/auth.ts b/src/server/auth.ts
index c05ae44..9c66005 100644
--- a/src/server/auth.ts
+++ b/src/server/auth.ts
@@ -21,6 +21,26 @@ function extractCookieValue(response: Response, name: string): string | undefine
   return undefined;
 }
 
+function getRequestOrigin(): string | undefined {
+  const origin = getRequestHeader('origin');
+  if (origin) return origin;
+
+  const referer = getRequestHeader('referer');
+  if (referer) {
+    try {
+      return new URL(referer).origin;
+    } catch {
+      return undefined;
+    }
+  }
+
+  const host = getRequestHeader('host');
+  if (!host) return undefined;
+
+  const proto = getRequestHeader('x-forwarded-proto') ?? 'http';
+  return `${proto}://${host}`;
+}
+
 export const adminLoginFn = createServerFn({ method: 'POST' })
   .inputValidator(
     z.object({
@@ -303,12 +323,17 @@ export const openIdCheckOptions = queryOptions({
 });
 
 export const checkOpenIdFn = createServerFn({ method: 'GET' }).handler(async () => {
+  const checkUrl = `${getServerApiUrl()}/api/admin/oauth/openid/check`;
   try {
-    const response = await fetch(`${getServerApiUrl()}/api/admin/oauth/openid/check`);
-    if (!response.ok) return { available: false, ssoOnly: false };
+    const response = await fetch(checkUrl);
+    if (!response.ok) {
+      console.warn('[checkOpenIdFn] OpenID check failed:', response.status, checkUrl);
+      return { available: false, ssoOnly: false };
+    }
     const ssoOnly = process.env.ADMIN_SSO_ONLY === 'true';
     return { available: true, ssoOnly };
-  } catch {
+  } catch (error) {
+    console.warn('[checkOpenIdFn] OpenID check request failed:', checkUrl, error);
     return { available: false, ssoOnly: false };
   }
 });
@@ -317,11 +342,12 @@ export const openidLoginFn = createServerFn({ method: 'GET' }).handler(async ()
   try {
     const baseUrl = getApiBaseUrl();
     const authUrl = new URL(`${baseUrl}/api/admin/oauth/openid`);
+    const requestOrigin = getRequestOrigin();
 
-    /** Generate PKCE code_verifier and store in session */
     const codeVerifier = crypto.randomBytes(32).toString('hex');
     const codeChallenge = crypto.createHash('sha256').update(codeVerifier).digest('hex');
     authUrl.searchParams.set('code_challenge', codeChallenge);
+    if (requestOrigin) authUrl.searchParams.set('redirect_uri', `${requestOrigin}/auth/openid/callback`);
 
     const session = await useAppSession();
     await session.update({ codeVerifier });
@@ -340,16 +366,9 @@ export const oauthExchangeFn = createServerFn({ method: 'POST' })
   .handler(async ({ data }) => {
     try {
       const headers: Record<string, string> = { 'Content-Type': 'application/json' };
-      const rawOrigin = getRequestHeader('origin') || getRequestHeader('referer');
-      if (rawOrigin) {
-        try {
-          headers['Origin'] = new URL(rawOrigin).origin;
-        } catch {
-          // malformed URL – skip forwarding
-        }
-      }
+      const requestOrigin = getRequestOrigin();
+      if (requestOrigin) headers['Origin'] = requestOrigin;
 
-      /** Read PKCE code_verifier from session (stored during openidLoginFn) */
       const session = await useAppSession();
       const { codeVerifier } = session.data;