https://www.hostinger.com/tutorials/vps/how-to-install-lets-encrypt-ssl-on-vps-running-vebmin-virtualmin

https://techjourney.net/how-to-use-lets-encrypt-ssl-certificate-automatically-in-virtualmin-webmin/

1. Edit the virtual server you want to SSL-enable
   1. Enable SSL feature
      • A self-signed certificate is automatically created and applied
2. Configure Let's Encrypt SSL certificate
   1. List the desired SANs

      domain.tld
      www.domain.tld
      mail.domain.tld
      autoconfig.domain.tld
      autodiscover.domain.tld

   2. Adjust the auto-renewal interval
      • The default (two months) is safe

Virtualmin → <domain> → Server Configuration → Manage SSL Certificate → Let’s Encrypt (tab)

Request certificate for → Domain names listed here → <list of Subject Alternative Names>

Months between automatic renewal → 2

Virtualmin → <domain> → Services → Configure Website → Aliases and Redirects

Permanent URL redirects → From → / (slash)

Permanent URL redirects → To → https://www.yourdomainname.tld

The matching domain name must be included in the SSL certificate.

Virtualmin → <domain> → Server Configuration → Manage SSL Certificate → Current Certificate (tab) → Copy to…

• Webmin
• Usermin
• Postfix
• Dovecot
• ProFTPD