diff --git a/djangochannelsrestframework/observer/generics.py b/djangochannelsrestframework/observer/generics.py
index fe3eec0..16c92df 100644
--- a/djangochannelsrestframework/observer/generics.py
+++ b/djangochannelsrestframework/observer/generics.py
@@ -72,7 +72,8 @@ def _subscribe(self, request_id: str, groups: Set[str]):
     def _unsubscribe(self, request_id: str):
         to_remove = []
         for group, request_ids in self.subscribed_requests.items():
-            request_ids.remove(request_id)
+            if request_id in request_ids:
+                request_ids.remove(request_id)
             if not request_ids:
                 to_remove.append(group)