Asynchronous Action Method Returns a Task, which cannot be Executed Synchronously

The error as given below.

System.InvalidOperationException' occurred in System.Web.Mvc.dll but was not handled in user code.

Additional information: The asynchronous action method 'Login' returns a Task, which cannot be executed synchronously.

The solution for the above error as given below in details.

Firstly, I have changed the application running process [5228] iisexpress.exe to [3840] ieexpoler.exe and run the application, error is resolved.

And the Second step below code changed.

var rc = new RequestContext( new HttpContextWrapper(Context), routeData);

controller.Execute(rc);

Replace above code by given below code.

((IController)controller).Execute(new RequestContext(new HttpContextWrapper(HttpContext.Current), routeData));

And In the 3rd Steps changed the name of login action

        [HttpPost]

        [AllowAnonymous]

        [ValidateAntiForgeryToken]

        public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)

        {

            //....... 

            // If we got this far, something failed, redisplay form

            return View(model);

        }

Replace the above action name Login to LoginUser.

        [HttpPost]

        [AllowAnonymous]

        [ValidateAntiForgeryToken]

        public async Task<ActionResult> LoginUser(LoginViewModel model, string returnUrl)

        {

            //...... 

            // If we got this far, something failed, redisplay form

            return View(model);

        }

Please see below video for how to changed the application process.