For example, I want to be able to get my login page as by /login and by /en/login route.
routes.MapRoute(
name: "LoginLang",
url: "{lang}/Login",
defaults: new { lang = "en", controller = "Account", action = "Login" }
);
But if /en/login gets accepted, route /login is not. It is treatable by an additional route, but still, do you have explanation why /login gets rejected?