Startup-Configure.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    // other configuration ...

    // Add SignalR hub routes
    app.UseSignalR(routes =>
    {
        routes.MapHub<GridEventsHub>("/hubs/gridevents");
    });

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });
}