signalR : /signalr/hubs is not generated

In my case, it was because my ChatHub class was not marked public.

Also, the reason why /signalr/hubs are not generated is forget to Map SignalR in OWIN Startup Configuration.

public class Startup
{
   public void Configuration(IAppBuilder appBuilder){
         ...
         appBuilder.MapSignalR();
         ...
   }
 ...

I have solved my problem by changing the line::

<script src="/signalr/hubs"></script>

to

<script src="~/signalr/hubs"></script>