using shiny-server with nginx

In step 3, configuring server block: is your_server_ip an actual IP address, domain name, or localhost? I have the following, but have tried ip address and local host. get 504 error code:

        root /var/www/data-dancer.com;
        index index.html;

        server_name data-dancer.com www.data-dancer.com;

        location / {
             proxy_pass http://data-dancer.com:3838;
             proxy_redirect http://data-dancer.com:3838 https://$host;
             proxy_http_version 1.1;
             proxy_set_header Upgrade $http_upgrade;
             proxy_set_header Connection $connection_upgrade;
             proxy_read_timeout 20d;
        }


    listen 443 ssl; # managed by Certbot
    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/data-dancer.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/data-dancer.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}

server {
    if ($host = www.data-dancer.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = data-dancer.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


        listen 80;
        listen [::]:80;

        server_name data-dancer.com www.data-dancer.com;
    return 404; # managed by Certbot
}