First, ensure you create a DNS entry for `room.your_instance.tld`, which points to your server.You can use a CNAME entry (or an A entry and a AAAA entry).This is necessary for Let's Encrypt to validate the domain for certificate generation.
Successfully received certificate. Certificate is saved at: /etc/letsencrypt/live/room.your_instance.tld/fullchain.pem Key is saved at:/etc/letsencrypt/live/room.your_instance.tld/privkey.pem