--- a/rest_auth_provider.py	2023-06-01 08:43:23.196158358 +0200
+++ b/rest_auth_provider.py	2023-06-01 08:44:11.764498766 +0200
@@ -26,6 +26,7 @@
 
 import synapse
 from synapse import module_api
+from synapse.types import UserID
 
 import logging
 import requests
@@ -112,10 +113,12 @@
         if not auth["success"]:
             logger.info("User not authenticated")
             return None
-        return auth       
+        return auth
 
     async def initialize_matrix_user(self, user_id, auth):
+        types_user_id = UserID.from_string(user_id)
         localpart = user_id.split(":", 1)[0][1:]
+        domain = user_id.split(":", 1)[1][1:]
         logger.info("User %s authenticated", user_id)
 
         registration = False
@@ -142,7 +145,7 @@
             if "display_name" in profile and ((registration and self.config.setNameOnRegister) or (self.config.setNameOnLogin)):
                 display_name = profile["display_name"]
                 logger.info("Setting display name to '%s' based on profile data", display_name)
-                await store.set_profile_displayname(localpart, display_name)
+                await store.set_profile_displayname(types_user_id, display_name)
             else:
                 logger.info("Display name was not set because it was not given or policy restricted it")