nginx.conf

server {
  listen 0.0.0.0:80;
  server_name koel.example.com
  server_tokens off;
	location '/.well-known/acme-challenge' {
		default_type "text/plain";
		root        /srv/http/letsencrypt;
	}
	location / {
	  return 301      https://$server_name$request_uri;
	}
}

## HTTPS host
server {
  listen 443;
  server_name koel.example.com;
  server_tokens off;

  client_max_body_size 50m;

  ## Strong SSL Security
  ## https://raymii.org/s/tutorials/Strong_SSL_Security_On_nginx.html & https://cipherli.st/
  ssl on;
  ssl_certificate 		fullchain.pem;
  ssl_certificate_key     privkey.pem;
  ssl_trusted_certificate		chain.pem;

  ssl_ciphers "ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4";
  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_prefer_server_ciphers on;
  ssl_session_cache shared:SSL:10m;
  ssl_session_timeout 5m;


  ## [WARNING] The following header states that the browser should only communicate
  ## with your server over a secure connection for the next 24 months.
  add_header Strict-Transport-Security max-age=63072000;
  add_header X-Frame-Options SAMEORIGIN;
  add_header X-Content-Type-Options nosniff;


  location / {
    proxy_pass http://localhost:10509;
  	proxy_set_header HOST $host;
  	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_redirect http://localhost:10509 $scheme://koel.example.com;
  	add_header Front-End-Https on;
  }
}