location /codeenv/ {

    # websocket proxy
    proxy_http_version 1.1;
    proxy_redirect off;
    proxy_buffering off;
    proxy_pass http://gisnotebook:7600;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    proxy_set_header Host $http_host;
    # proxy_set_header Host $host; # NOT WORKING!
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_read_timeout 3600;
    proxy_send_timeout 3600;
}