diff --git a/backend/pkg/db/cache/messages_common.go b/backend/pkg/db/cache/messages_common.go
index cc5d54f2c..63c63d773 100644
--- a/backend/pkg/db/cache/messages_common.go
+++ b/backend/pkg/db/cache/messages_common.go
@@ -39,7 +39,7 @@ func (c *PGCache) InsertUserID(sessionID uint64, userID *IOSUserID) error {
 	if err != nil {
 		return err
 	}
-	session.UserID = userID.Value
+	session.UserID = sql.NullString{userID.Value,true}
 	return nil
 }