first,upgrade your nginx server to 1.3 or higher.
second,my nginx conf works.you can follow my conf.
server {
listen 80;
server_name jn.whattoc.com;
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://127.0.0.1:4050/;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}