diff --git a/api/src/api/v1/websocket.py b/api/src/api/v1/websocket.py
index 9768e9f..5638799 100644
--- a/api/src/api/v1/websocket.py
+++ b/api/src/api/v1/websocket.py
@@ -326,7 +326,7 @@ class ConnectionManager:
             if form_key != form_key or lock_owner_id == user_id:
                 continue
 
-            for k, v in cell_key.items():
+            for k, v in cell_key:
                 if k == "line_id" and v == line_id:
                     lock_keys.append(lock_key)