diff --git a/Changes.txt b/Changes.txt
index 765bedee8..689c219d8 100644
--- a/Changes.txt
+++ b/Changes.txt
@@ -11,6 +11,8 @@
     `umount.s3ql`, `umount`, or `fusermount -u` and wait for the mount.s3ql process to
     terminate.
 
+  * More robust expired auth token detection for Google Storage.
+
 
 2020-11-09, S3QL 3.6.0
 
diff --git a/src/s3ql/backends/gs.py b/src/s3ql/backends/gs.py
index 730c16a78..10167eb1b 100644
--- a/src/s3ql/backends/gs.py
+++ b/src/s3ql/backends/gs.py
@@ -436,12 +436,11 @@ def write_fh(self, fh, key: str, md5: bytes,
             raise ValueError('md5 passed to write_fd does not match fd data')
 
         resp = self.conn.read_response()
-        if resp.status != 200:
+        # If we're really unlucky, then the token has expired while we were uploading data.
+        if resp.status == 401:
+            raise AccessTokenExpired()
+        elif resp.status != 200:
             exc = self._parse_error_response(resp)
-            # If we're really unlucky, then the token has expired while we
-            # were uploading data.
-            if exc.message == 'Invalid Credentials':
-                raise AccessTokenExpired()
             raise _map_request_error(exc, key) or exc
         self._parse_json_response(resp)