subdomain.domain.com.br

server {

        server_name subdomain.domain.com.br;

        error_page 500 502 503 504 /custom_50x.html;
        location = /custom_50x.html {
                root /usr/share/nginx/html;
                internal;
        }

        index index.html index.htm index.nginx-debian.html;

        location ^~ /assets/ {
                gzip_static on;
                expires 12h;
                add_header Cache-Control public;
        }

        location / {
                proxy_http_version 1.1;
                proxy_cache_bypass $http_upgrade;

                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection 'upgrade';
                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_pass http://localhost:4000;
        }


        listen [::]:443 ssl;
        listen 443 ssl;

}

server {

        if ($host = subdomain.domain.com.br) {
            return 301 https://$host$request_uri;
        }

        listen 80;
        listen [::]:80;

        server_name subdomain.domain.com.br;
        return 404;

}

ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/