diff --git a/vdirsyncer/storage/dav.py b/vdirsyncer/storage/dav.py
index 727f685..dc9085f 100644
--- a/vdirsyncer/storage/dav.py
+++ b/vdirsyncer/storage/dav.py
@@ -422,6 +422,7 @@ class DAVSession:
         return aiohttp.ClientSession(
             connector=self.connector,
             connector_owner=False,
+            trust_env=True,
             # TODO use `raise_for_status=true`, though this needs traces first,
         )
 
diff --git a/vdirsyncer/storage/http.py b/vdirsyncer/storage/http.py
index 5b12098..177e769 100644
--- a/vdirsyncer/storage/http.py
+++ b/vdirsyncer/storage/http.py
@@ -68,6 +68,7 @@ class HttpStorage(Storage):
         async with aiohttp.ClientSession(
             connector=self.connector,
             connector_owner=False,
+            trust_env=True,
             # TODO use `raise_for_status=true`, though this needs traces first,
         ) as session:
             r = await request(