Nginx websocket 502 puerta de enlace incorrecta

Question

Estoy intentando usar nginx como proxy para el servidor websocket nodejs, pero siempre obtengo 502 puerta de enlace incorrecta.

mi configuración de dominio:

upstream server {
  server 127.0.0.1:8090;
}

server {
 listen 8085;
 server_name server.cz server;
 ssl on;
 #ssl_certificate /etc/ssl/server/server.cz.pem;
 ssl_certificate /etc/ssl/server/server.cz.crt;
 ssl_certificate_key /etc/ssl/server/server.cz.key;

 access_log /var/log/nginx/server.log;
 location / {
  proxy_set_header X-Real-IP $remote_addr;
  proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  proxy_set_header Host $http_host;
  proxy_set_header X-NginX-Proxy true;

  proxy_pass http://server;
  proxy_redirect off;

  #WEBSOCKET
  proxy_http_version 1.1;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection "upgrade";
 }
}

Estoy probando esto con curl:

curl -i -N -vv -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: server.cz" -H "Origin: https://server.cz" -k https://127.0.0.1:8085

Esto dará como resultado 502 resultado completo de puerta de enlace incorrecta:http://pastebin.com/bL1CYzjt

Si intento esto directamente en el servidor Nodejs, funciona bien.

Registro de Nginx:

[error] 4083#0: *1 upstream prematurely closed connection while reading response header from upstream, client: 127.0.0.1, server: server.cz, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8090/", host: "server.cz"

servidor.log

"GET / HTTP/1.1" 502 172 "-" "curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3"