diff --git a/backend/app/routers/shared_calendars.py b/backend/app/routers/shared_calendars.py
index b9ed123..1531412 100644
--- a/backend/app/routers/shared_calendars.py
+++ b/backend/app/routers/shared_calendars.py
@@ -60,7 +60,7 @@ def _build_member_response(member: CalendarMember) -> dict:
         "calendar_id": member.calendar_id,
         "user_id": member.user_id,
         "umbral_name": member.user.umbral_name if member.user else "",
-        "preferred_name": member.user.preferred_name if member.user else None,
+        "preferred_name": None,
         "permission": member.permission,
         "can_add_others": member.can_add_others,
         "local_color": member.local_color,