My domain is: host.lrnodes.tk
I ran this command:
certbot --nginx -d host.lrnodes.tk
It produced this output:
root@Root:~# certbot --nginx -d host.lrnodes.tk Saving debug log to /var/log/letsencrypt/letsencrypt.log Requesting a certificate for host.lrnodes.tk Certbot failed to authenticate some domains (authenticator: nginx). The Certificate Authority reported these problems: Domain: host.lrnodes.tk Type: unauthorized Detail: 2001:41d0:303:63c3::258: Invalid response from http://host.lrnodes.tk/.well-known/acme-challenge/1zAeeroYeIyKH4aQOv55sM73FYg_-R6SN1bS4vq-Ib8: 404 Hint: The Certificate Authority failed to verify the temporary nginx configuration changes made by Certbot. Ensure the listed domains point to this nginx server and that it is accessible from the internet. Some challenges have failed. Ask for help or search for solutions at https://community.letsencrypt.org. See the logfile /var/log/letsencrypt/letsencrypt.log or re-run Certbot with -v for more details.