1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 95bb06395a..5fd20285d2 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -93,7 +93,7 @@ class BaseHandler(object):
             membership_event = state.get((EventTypes.Member, user_id), None)
             if membership_event:
                 was_forgotten_at_event = yield self.store.was_forgotten_at(
-                    membership_event.user_id,
+                    membership_event.state_key,
                     membership_event.room_id,
                     membership_event.event_id
                 )