Socket.io with NGINX and https2

I have node.js app which is served by NGINX. I can't connect socket.io. I got 404 for POST request for establising socket connection.

It's working locally, so it must be an NGINX problem.

  # HTTP - redirect all requests to HTTPS:
  server {
     listen 80;
     listen [::]:80;
     return 301 https://$host$request_uri;
  }
  # HTTPS - proxy requests on to local Node.js app:
  server {
     listen 443 ssl http2;
     server_name example.com;
     ssl on;
     ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
     ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
     ssl_session_timeout 5m;
     ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
     ssl_prefer_server_ciphers on;
     ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';
     location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-NginX-Proxy true;
        proxy_set_header X-Forwarded-Proto https;
        proxy_pass http://127.0.0.1:8080;
        proxy_ssl_session_reuse off;
        proxy_set_header Host $http_host;
        proxy_cache_bypass $http_upgrade;
        proxy_redirect off;
     }
}

Thanks for any help.

via Matej Maloča