return View() and return PartialView() mystery MVC5

Question

I'm using MVC 5 with Identity 2.0 for security. When I start the application it displays login page (without layout probably because I'm returning partial view). When I use return View() instead of return PartialView() it gives me following error;

HTTP Error 404.15 - Not Found The request filtering module is configured to deny a request where the query string is too long.

I enabled both windows and Anonymous authentication of website but it is not working. My action for login is

 [AllowAnonymous]
 public ActionResult Login(string returnUrl)
 {
     ViewBag.ReturnUrl = returnUrl;
     return PartialView();
 }       

Answer 1

your issue it's not the MVC code it's more an IIS configuration take a look at the following link

http://www.iis.net/configreference/system.webserver/security/requestfiltering/alwaysallowedquerystrings