Manage Map Cache using ArcGIS Server 10.4 REST API using C#.net

I am trying to use the ArcGIS Server 10.4 REST API to manage map caches via C#.NET, System.Net.Http. I am able to access and utilize the REST API with this technology, so I know it can work. But this specific attempt fails every time with the following error:

Error executing tool. Manage Map Cache Tiles Job ID: j89eeb39daaba427891dcc5cefe90a0d0 : ERROR 001428: Failed to retrieve configuration for service http://arcgistest.domain.net:6080/arcgis/rest/services/TestServices/TestPoints/MapServer/. Failed to execute (Manage Map Cache Tiles).

As you can see by the error message I am able to submit a job to the proper service (that is after generating a token, which is required for the System geoprocessing services). Furthermore, if I remove one of the required parameters I get a message telling me so. This helps me to know I'm on the right track.

My best guess is the "service_url" parameter is not correct but the documentation on what to supply here is not helpful and mainly for python applications which will be running on a local machine. My goal is to create a service wrapper for a non-gis developer...

private static void TryMapCache(string[] args, string token)
    {

        args = new string[7];
        string url = "http://arcgistest.domain.net:6080/arcgis/rest/services/System/CachingTools/GPServer/";

        args[0] = "Manage%20Map%20Cache%20Tiles/SubmitJob?";
        args[1] = "service_url=http://arcgistest.domain.net:6080/arcgis/rest/services/TestServices/TestPoints/MapServer;             
        args[2] = "&levels=1155581.108577;577790.554289";
        args[3] = "&thread_count=6";
        args[4] = "&update_mode=RECREATE_ALL_TILES";
        args[5] = "&f=pjson";
        args[6] = "&token=" + token;



        StringBuilder urlParameters = new StringBuilder();
        urlParameters.Append(args[0].ToString());
        urlParameters.Append(args[1].ToString());
        urlParameters.Append(args[2].ToString());
        urlParameters.Append(args[3].ToString());
        urlParameters.Append(args[4].ToString());
        urlParameters.Append(args[5].ToString());
        urlParameters.Append(args[6].ToString());


        Console.WriteLine(url + urlParameters.ToString());

        HttpClient theClient = new HttpClient();
        theClient.BaseAddress = new Uri(url);

        //data response
        HttpResponseMessage theResponse = theClient.GetAsync(urlParameters.ToString()).Result;
        if (theResponse.IsSuccessStatusCode)
        {

            string responseData = theResponse.Content.ReadAsStringAsync().Result;
            Console.WriteLine(responseData);
            Console.ReadKey();
        }
    }

This is the output:

{ "jobId": "j8f9f5f6412ac4d688540bad252cfee3e", "jobStatus": "esriJobSubmitted" }

Answer

I took the advice of KHibma -make an answer- and looked at the communication between ArcMap and ArcGIS Server using Fiddler. As expected, the "service_url" was incorrect.

I was using the rest service URL (which is incorrect): http://arcgistest.domain.net:6080/arcgis/rest/services/TestServices/TestPoints/MapServer

Instead, ArcMap sends the following text in the "service_url" parameter (which is correct): "TestServices/TestPoints:MapServer"

where "TestServices" is the Service directory and "TestPoints" is the Map Service.

The following code successfully re-created the map cache.

private static void TryMapCache(string[] args, string token)
    {
        args = new string[7];
        string url = "http://arcgistest.domain.net:6080/arcgis/rest/services/System/CachingControllers/GPServer/";

        args[0] = "Manage Map Cache Tiles/SubmitJob?";

        args[1] = "service_url=TestServices/TestPoints:MapServer";
        args[2] = "&levels=1155581.108577;577790.554289";
        args[3] = "&thread_count=6";
        args[4] = "&update_mode=RECREATE_ALL_TILES";
        args[5] = "&f=pjson";
        args[6] = "&token=" + token;


        StringBuilder urlParameters = new StringBuilder();
        urlParameters.Append(args[0].ToString());

        urlParameters.Append(args[1].ToString());
        urlParameters.Append(args[2].ToString());
        urlParameters.Append(args[3].ToString());
        urlParameters.Append(args[4].ToString());
        urlParameters.Append(args[5].ToString());
        urlParameters.Append(args[6].ToString());

        Console.WriteLine(url + urlParameters.ToString());

        HttpClient theClient = new HttpClient();

        theClient.BaseAddress = new Uri(url);

        //data response
        HttpResponseMessage theResponse = theClient.GetAsync(urlParameters.ToString()).Result;
        if (theResponse.IsSuccessStatusCode)
        {
            //parse the response body
            string responseData = theResponse.Content.ReadAsStringAsync().Result;
            Console.WriteLine(responseData);
            Console.ReadKey();

        }
    }