diff --git a/mautrix/api.py b/mautrix/api.py
index d034149b..4d421bd7 100644
--- a/mautrix/api.py
+++ b/mautrix/api.py
@@ -230,7 +230,7 @@ def __init__(
         self.token = token
         self.log = log or logging.getLogger("mau.http")
         self.session = client_session or ClientSession(
-            loop=loop, headers={"User-Agent": self.default_ua}
+            loop=loop, headers={"User-Agent": self.default_ua}, trust_env=True
         )
         self.as_user_id = as_user_id
         self.as_device_id = as_device_id
diff --git a/mautrix/client/api/base.py b/mautrix/client/api/base.py
index 07659894..f6c48abc 100644
--- a/mautrix/client/api/base.py
+++ b/mautrix/client/api/base.py
@@ -136,7 +136,7 @@ async def discover(cls, domain: str, session: ClientSession | None = None) -> UR
             WellKnownError: for other errors
         """
         if session is None:
-            async with ClientSession(headers={"User-Agent": HTTPAPI.default_ua}) as sess:
+            async with ClientSession(headers={"User-Agent": HTTPAPI.default_ua}, trust_env=True) as sess:
                 return await cls._discover(domain, sess)
         else:
             return await cls._discover(domain, session)