diff --git a/ldapauthenticator/ldapauthenticator.py b/ldapauthenticator/ldapauthenticator.py
index c188e05..20f33f3 100644
--- a/ldapauthenticator/ldapauthenticator.py
+++ b/ldapauthenticator/ldapauthenticator.py
@@ -264,7 +264,7 @@ def resolve_username(self, username_supplied_by_user):
             "Looking up user with:\n",
             f"    search_base = '{self.user_search_base}'\n",
             f"    search_filter = '{search_filter}'\n",
-            f"    attributes = '{self.user_attribute}'",
+            f"    attributes = '[{self.lookup_dn_user_dn_attribute}]'",
         )
         conn.search(
             search_base=self.user_search_base,