diff --git a/persistence/cosmos.py b/persistence/cosmos.py
index 79758b22..fe1678ae 100644
--- a/persistence/cosmos.py
+++ b/persistence/cosmos.py
@@ -54,8 +54,10 @@ async def call_asearch_one(self, phone_number: str) -> Optional[CallModel]:
             parameters=[
                 {
                     "name": "@date_limit",
-                    "value": datetime.utcnow()
-                    + timedelta(hours=CONFIG.workflow.conversation_timeout_hour),
+                    "value": str(
+                        datetime.utcnow()
+                        + timedelta(hours=CONFIG.workflow.conversation_timeout_hour)
+                    ),
                 }
             ],
         )