ErrorController

    public class ErrorController : Controller
    {
        public ILogger Logger { get; set; }

        public ActionResult Error(int code = 404, string redirectedUrl = "")
        {
            ViewBag.StateCode = code;
            if (code == 401)
                if (!string.IsNullOrEmpty(redirectedUrl))
                    return Redirect(redirectedUrl);
            return View("Error");
        }
    }