>>>Network tab on the browser debugger should show you the request ?
>>>
>>>Update: just realised that this must be on the server - in which case Fiddler should let you see the request that went over the wire
>>
>>I am using Google Chrome and I'm just running the code from VS - what should I do exactly?
>
>You're kidding, right?

No.

I really don't know how to debug this. I have Dev Tools in Chrome opened, but they don't show anything useful. In the VS I'm trying to examine the response object but it also doesn't help much.

I see the following:

{StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Pragma: no-cache
Cache-Control: no-cache
Date: Mon, 21 Nov 2016 11:15:01 GMT
Server: Microsoft-IIS/8.5
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Content-Length: 77
Content-Type: text/plain; charset=utf-8
Expires: -1
}}


{Method: POST, RequestUri: 'URL here', Version: 1.1, Content: System.Net.Http.ObjectContent`1[[Siriusware.CityPASS.TicketUsageRequests, CityPASS, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], Headers:
{
Accept: application/json
Authorization: Basic String goes here
Content-Type: application/json; charset=utf-8
Content-Length: 117
}}

'((System.RuntimeType)((System.Net.Http.ObjectContent)response.RequestMessage.Content).ObjectType).DeclaringMethod' threw an exception of type 'System.InvalidOperationException' (if I try go to deep inside).

This is the first time I'm trying to work with HttpClient, so I don't really know what I am supposed to do. I have API from the client and I'm trying to follow the sample, but I don't know if I am missing something or not.