Rancher 1.6 websocket does not work

Question

I’m having trouble using Socket.IO inside Rancher 1.6. Websocket connections sometimes even work but most of the time it is giving 503 or 502 error. I tried some settings within Haproxy to make Websocket work but without success, here are my settings

global
  maxconn 4096

defaults
  mode http
  balance roundrobin
  option redispatch
  option forwardfor

  timeout connect 1800000ms
  timeout queue 30s
  timeout client 1800000ms
  timeout server 1800000ms

frontend http-in
  mode http
  bind *:3000
  maxconn 60000

  acl is_websocket hdr(Connection) -i upgrade
  acl is_websocket hdr(Upgrade) -i WebSocket
  acl is_websocket hdr_beg(Host) -i ws
  use_backend ws_server if is_websocket
  default_backend www

backend www
  timeout connect 1800000ms
  timeout client 1800000ms
  timeout server 1800000ms
  server servidor_http <IP INTERNO DO RANCHER>:2456

backend ws_server
  server servidor_ws <IP INTERNO DO RANCHER>:2456 weight 1 maxconn 1024

Does anyone know where I’m going wrong? And how to run the websocket within Rancher 1.6?