100K sized POST requests don't get to webAPI?

Question

I'm using Fiddler (or post manager) to invoke requests to my WebApi. ( it's hosted as an ASP.net application in IIS)

This is the service :

    [HttpPost]
    [ActionName("uploadRessources")]
    [AllowAnonymous]
    public HttpResponseMessage uploadRessources(ResourcesJson json)
    {
      ...
        return Request.CreateResponse(HttpStatusCode.OK, result);
    }

For short length body( 3 rows of data) length post data requests like :

POST http://something.com/api/services/uploadRessources HTTP/1.1
Cache-Control: no-cache
Connection: keep-alive
Pragma: no-cache
Accept: application/json
Accept-Encoding: gzip
Accept-Language: he-IL
User-Agent: Mozilla/5.0
Content-Length: 451
Content-Type: application/json
Host: es.com

{ "l":
[{"MasterEntity":2,"screen":"ConfirmHealthDetailsPage","Lbl":"ApproveTheFollowingDetails","enus":"Approve the Following Details:","device":"mobile","description":"NULL"},
{"MasterEntity":2,"screen":"ConfirmHealthDetailsPage","Lbl":"PersonalDetails","enus":"Personal Details","device":"mobile","description":"NULL"},
{"MasterEntity":2,"screen":"FingerPrintResources","Lbl":"CANCEL","enus":"CANCEL","device":"mobile","description":"NULL"}]
 }

I DO get a successful response :

HTTP/1.1 200 OK

But for a long body length request ( 101K ) -

It is stuck (it even doesn't hit the breakpoint in my code , while in short request - it does )and I never see a response :

BTW - If later I do run again the short body length request( while still waiting for the previous large requests) - I do get 200 ( for the short length request).

In web.config I did set :

<httpRuntime enableVersionHeader="false" executionTimeout="100000000" maxRequestLength="999999999" />

In IIS : No requests filters
In Event Viewer - I don't see any exceptions or warnings IIS version : 6.1 ( windows 7) - but it also happens at our server.

Question

Why doesn't my 101k length request - get to my webapi ?

Edit

I've found that it happens for >65k requests. Still don't know what is the problem

Answer 1

It was stuck on request.Content.ReadAsStringAsync().Result ( and never released). Strange but setting it to async , solved the problem. I still don't know why. In General this is the solution - the left pane was the problematic one while the right pane is the working one. ( I must say that the left pane used to work , but after upgrading to 4.6.2 - it started doing problems) - Again - I don't know why

Answer 2

It's seems to be an issue with your serializer, tries to put a breakpoint there and see if hits it. If you are not using a custom serializer, creates one temporally just to see what's happen with your request.