Update tasks fields from request additional field - again :)

I need to automatically complete the task fields with the start and end date based on an additional field in the request. I have the following script but it doesn't work properly. After launching, it throws the error "{"result":"Failure","message":"Task fetch failed"}" Please help me because I'm out of ideas :)

SDP MSP 14.000

technician key is configured :)

configuration = global_function_10();
dateOfJoining = "udf_date_904";

helpdeskID = context.get("instance").get("id");
workorderid = requestObj.get('id');
json_data = {"list_info": { "row_count": "100"} };

taskresponse = invokeurl
[
   url: configuration.get('url') + "/api/v3/requests/"+workorderid+"/tasks"
   type: GET
   headers: {"authtoken":configuration.get("technicianKey"),"PORTALID":helpdeskID}
   parameters: {"input_data":json_data}
];
successList = List();
failureList = List();
resultantJson = Map();

schedule_end_date = requestObj.get("udf_fields").get(dateOfJoining).get("value");
additionalField = requestObj.get("udf_fields").get(dateOfJoining).get("display_value").toDateTime();
additionalField = additionalField.subDay(7);
schedule_start_date = additionalField.toString().unixEpoch("Asia/Calcutta");

info schedule_start_date;

if("success".equalsIgnoreCase(taskresponse.get("response_status").get("status")))
{
   taskData = taskresponse.get('tasks');
   for each task in taskData{
        input_data = {
                "task": {
                        "scheduled_start_time": {"value":schedule_start_date },
                        "scheduled_end_time": {"value":schedule_end_date }
                        }
                    };

        response = invokeurl
        [
            url: configuration.get('url') + "/api/v3/requests/"+workorderid+"/tasks/" + task.get("id")
            type: PUT
            headers: {"authtoken":configuration.get("technicianKey"),"PORTALID":helpdeskID}
            parameters: {"input_data":input_data}
        ];

        if("success".equalsIgnoreCase(response.get("response_status").get("status")) ){
            successList.add(task.get('id'));
        }
        else{
            failureList.add(task.get('id'));
        }
   }
   msg = "";
   if(!successList.isEmpty()){
        msg = "List of Tasks successfully edited: " + successList;
   }
   if(!failureList.isEmpty()){
        msg = msg + ",   List of Tasks failed to Edit: " +failureList;
   }
   resultantJson.insert("result": "Success","message": msg);
}
else{
   resultantJson.insert("result": "Failure","message": "Task fetch failed");
}
return resultantJson;