Memorandum on using the certbot command to obtain a "Let's Encrypt" SSL certificate.

If you place the certification file in the document root of a public directory and retrieve it

$ certbot certonly --webroot -w [public directory] -d XXXXXXX.xxx -m -m [mail-address]

To authenticate by inserting a TXT record for authentication in the DNS

$ certbot certonly --manual -d XXXXXXX.xxx --preferred-challenges dns -m [mail-address]

If you register your e-mail address, you will be notified when your certificate is about to expire.