diff --git a/ProtuSAML/__init__.py b/ProtuSAML/__init__.py
index 74ad932..cfcb6b5 100644
--- a/ProtuSAML/__init__.py
+++ b/ProtuSAML/__init__.py
@@ -60,7 +60,7 @@ class SAMLMappingProviderProtuEdition:
         self._mxid_mapper = parsed_config.mxid_mapper
 
         self._grandfathered_mxid_source_attribute = (
-            module_api._hs.config.saml2_grandfathered_mxid_source_attribute
+            module_api._hs.config.saml2.saml2_grandfathered_mxid_source_attribute
         )
 
     def get_remote_user_id(
@@ -156,4 +156,4 @@ class SAMLMappingProviderProtuEdition:
                 second set consists of those attributes which can be used if
                 available, but are not necessary
         """
-        return {"uid", config.mxid_source_attribute}, {"displayName", "email"}
\ No newline at end of file
+        return {"uid", config.mxid_source_attribute}, {"displayName", "email"}