diff --git a/app/core/models/user_activity.py b/app/core/models/user_activity.py
index 6f39ef6..99f8291 100644
--- a/app/core/models/user_activity.py
+++ b/app/core/models/user_activity.py
@@ -11,7 +11,7 @@ class UserActivity(AlchemyBase):
     type = Column(String(64), nullable=False)
     meta = Column(JSON, nullable=False, default={})
 
-    user_id = Column(Integer, ForeignKey('users.id'), nullable=False)
+    user_id = Column(Integer, ForeignKey('users.id'), nullable=True)
     user_ip = Column(String(64), nullable=True)
     created = Column(DateTime, nullable=False, default=0)