1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 41a35ce510..a0b4a93ae8 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -244,7 +244,7 @@ class MessageHandler:
                 )
                 room_state = room_state_events[membership_event_id]
 
-        events = self._event_serializer.serialize_events(
+        events = await self._event_serializer.serialize_events(
             room_state.values(),
             self.clock.time_msec(),
             config=SerializeEventConfig(requester=requester),