Update api/routes.py

api/routes.py

@@ -195,9 +195,12 @@ async def list_doctor_appointments(current_user: dict = Depends(get_current_user
     appointments = []
 
     async for a in cursor:
-        patient_id = a.get("patient_id")
         try:
-            patient = await users_collection.find_one({"_id": ObjectId(patient_id)})
+            patient_id = a.get("patient_id")
+            if not isinstance(patient_id, ObjectId):
+                patient_id = ObjectId(patient_id)
+
+            patient = await users_collection.find_one({"_id": patient_id})
         except Exception:
             patient = None