Port 8888 not working (websockets)

Yea my question is where is the setting for this port and how can I get 8888 working? I tried the port 80 but then you get a 404. And with port 8888 i get the next error connection refused. But if you look at the example in the websocket github then you see he uses port 8888. I think this is the port the websocket can use, if correctly installed.