stream {
    upstream leylines {
        server 127.0.0.1:31338;
    }
    server {
        listen your_public_ip:31337 ssl;
        proxy_pass leylines;
        ssl_certificate /etc/letsencrypt/live/your_domain_name/fullchain.pem;
        ssl_certificate_key /etc/letsencrypt/live/your_domain_name/privkey.pem;
        include options-ssl-stream.conf;
        ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;
    }
}