Websocket connection works in chrome but fails to connect in firefox?
You're getting a 400 Bad Request back for Firefox users. It isn't immediately apparent as to why. The request data between Firefox and Chrome is almost identical. The only difference I see is Chrome has more for this header:
Sec-Websocket-Extensions: permessage-deflate; client_max_window_bits=10; server_no_context_takeover; client_no_context_takeover; server_max_window_bits=10.