The provided anti-forgery token was meant for a different claims-based user than the current user: MVC4

We have a website that automatically logs out after 20 minutes of idle time. Below is code in _layout.ts:

var idleMax = 200;// Logout after 20 minutes of IDLE
var idleTime = 0;
var baseUrl = '<some url>'; // like: 'http://localhost/'
var webServerUri  = '<some url>'

function timerIncrement() {
    idleTime = idleTime + 1;
    if (idleTime > idleMax) {
        idleTime = 0;
        $.ajax({
            url: baseUrl + "Sys/Home/Logoff"
        });
        window.location.replace(webServerUri + "Sys/Home/Login?returnUrl=" + window.location.href.replace(/&/gi, "%26") + "&isInactive=-1");
    }
}

HomeController.cs:

Sys/Home/Logoff: 

  public ActionResult Logoff()
        {
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            Response.Cache.SetExpires(DateTime.UtcNow.AddMinutes(-1));
            Response.Cache.SetNoStore();
            HttpContext.GetOwinContext().Authentication.SignOut();
            return Redirect(VirtualPathUtility.ToAbsolute("~/") + "sys/Home/Login");
        }

Login action: (showing login page):

    [AllowAnonymous]
        public ActionResult Login(string returnUrl)
        {
            ViewBag.ReturnURL = returnUrl;
            if (!String.IsNullOrWhiteSpace(returnUrl))
            {
                Response.Cache.SetCacheability(HttpCacheability.NoCache);
                Response.Cache.SetExpires(DateTime.UtcNow.AddMinutes(-1));
                Response.Cache.SetNoStore();
               // HttpContext.GetOwinContext().Authentication.SignOut();

                ViewBag.ReturnURL = returnUrl.Replace("&", "%26");
            }
            return View();
        }

login.cshtml has begin form section as below:

   @using (Html.BeginForm(new { ReturnUrl = ViewBag.ReturnUrl }))
                {
                    @Html.AntiForgeryTokenNoEx()
.
.
.
.<Other code>
.
.
.
.
}

User log out after 20 minutes of idle time. then we again enter same username and password and it gives below error:

The provided anti-forgery token was meant for a different claims-based user than the current user