you have to add namespaces of your controller in RegisterArea method:
public override void RegisterArea(AreaRegistrationContext context)
{
context.MapRoute(
"ImportNightflight_default",
"ImportNightflight/{controller}/{action}/{id}",
new { action = "Index", id = UrlParameter.Optional }
namespaces: new[] {"Write your controller's namespace"}
);
}
For more help visit:
Areas in ASP.NET MVC 4[
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