When i open this page RichFaces Showcase - Push Messages

I have error in browser:

WebSocket connection to 'ws://showcase.richfaces.org/__richfaces_push?__richfacesPushAsync=1&pushSessionId=0700d786-0f7e-4c01-8b19-5b9acbfa5d43&X-Atmosphere-tracking-id=0&X-Atmosphere-Framework=2.3.2-javascript&X-Atmosphere-Transport=websocket&X-atmo-protocol=true' failed: Error during WebSocket handshake: Unexpected response code: 501

This error in my project too

It is normal?