SignalR /signalr/hubs 404 Not Found

The order of route registration matters. I had this exact problem and fixed it by ensuring my global.asax.cs looked like this:

public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        RouteTable.Routes.MapHubs();

        WebApiConfig.Register(GlobalConfiguration.Configuration);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
    }
}

This was in a web site using SignalR, MVC and WebApi all together.