When I call the client like

var post = client.PostAsync("http://localhost:32510/api/something",
                             new StringContent(doc.ToString()));

I am not able to break into any of my code on the server side, instead I just get a 500

 var responseDoc = post.Result.Content.ReadAsStringAsync().Result;

It looks like the response comes back as a JSON serialized exception?

{"ExceptionType":"System.InvalidOperationException","Message":"No 'MediaTypeFormatter' is available to read an object of type 'HttpRequestMessage' with the media type 'text\/plain'.","StackTrace":"   at System.Net.Http.ObjectContent.SelectAndValidateReadFormatter(Boolean acceptNullFormatter)\u000d\u000a   at System.Net.Http.ObjectContent.ReadAsyncInternal[T](Boolean allowDefaultIfNoFormatter)\u000d\u000a   at System.Web.Http.ModelBinding.RequestContentReader.ReadWholeBodyAsync(HttpActionContext actionContext, Type modelType)\u000d\u000a   at System.Web.Http.ModelBinding.RequestContentReader.ReadContentAsync(HttpActionContext actionContext)\u000d\u000a   at System.Web.Http.ModelBinding.DefaultActionValueBinder.BindValuesAsync(HttpActionContext actionContext, CancellationToken cancellationToken)\u000d\u000a   at System.Web.Http.ApiController.<>c__DisplayClass3.b__0()\u000d\u000a at System.Web.Http.ApiController.ExecuteAsync(HttpControllerContext controllerContext, CancellationToken cancellationToken)\u000d\u000a at System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsyncInternal(HttpRequestMessage request, CancellationToken cancellationToken)\u000d\u000a at System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)"}