It seems you are missing controller segment after Area in the code you wrote above. It should be something like:
public override void RegisterArea(AreaRegistrationContext context) { context.MapRoute( "Internal_default", "Intranet/{controller}/{action}/{id}", new { action = "Index", id = UrlParameter.Optional }, namespaces: new[] { "Your Controller Namespace" } ); }
A related question at below link is answered, hope that will help too: Controller with same name as an area - Asp.Net MVC4