Change the Domain-Name

This is the part below that handles the Libretime server. It is in the file /etc/nginx/sites-available/music.conf

On the Libretime server I link back to the same SSL cert files (or copy them with a cron job) so that Libretime also uses SSL.

server {
    if ($host = libretime.xyz.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot

    listen 80;
    server_name libretime.xyz.com;

    location / {
        proxy_pass http://192.168.7.66;
        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;
    }
}

server {
    listen 443 ssl;
    server_name libretime.xyz.com;

    location / {
        proxy_pass https://192.168.7.66;
        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;
    }

    ssl_certificate /etc/letsencrypt/live/libretime.xyz.com/fullchain.pem; # man$
    ssl_certificate_key /etc/letsencrypt/live/libretime.xyz.com/privkey.pem; # m$
}