ASP.NET Controller: An asynchronous module or handler completed while an asynchronous operation was still pending

Question

I have a very simple ASP.NET MVC 4 controller:

public class HomeController : Controller
{
    private const string MY_URL = \"http://smthing\";
    private r         


        

Answer 1

I had this error today when building an API controller. It turned out that the solution was simple in my case.

I had:

public async void Post()

And I needed to change it to:

public async Task Post()

Note, the compiler did not warn about async void.