diff --git a/snikket_web/prosodyclient.py b/snikket_web/prosodyclient.py
index 56d5f86..13d9e1f 100644
--- a/snikket_web/prosodyclient.py
+++ b/snikket_web/prosodyclient.py
@@ -434,7 +434,7 @@ class ProsodyClient:
             auth_info: typing.Mapping[str, str] = (await resp.json())
 
             if auth_status in [400, 401]:
-                self.logger.debug("oauth2 error: %r", auth_info)
+                self.logger.warning("oauth2 error: %r", auth_info)
                 # OAuth2 spec says that’s what can happen when some stuff is
                 # wrong.
                 # we have to interpret the JSON further