php websocket连接建立错误

I have installed Symfony 3 on Ubuntu LAMP stack (PHP 7). I need websockets on my website so I:

  1. Added gos/web-socket-bundle to my symfony via composer

  2. Set config:

gos_web_socket: server: port: 4000 host: mydomain.com

  1. Opened port via firewall sudo ufw allow 4000/tcp and sudo ufw allow 4000.

  2. Then I started server php bin/console gos:websocket:server and it's running.

But when I try to connect from js:

var ws = new WebSocket('ws://mydomain.com:4000');

It gives the error:

WebSocket connection to 'ws://mydomain.com:4000/' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED

The comment provided by @drew010 resolved this for me.

In config.yml set gos_web_socket.server.host to 0.0.0.0.