SSL Certificate mail.domain.com

Hello!
I currently have problems for SSL mail.domain.com
I did not have problems for SSL server-host and domain.com

If I generate a manual SSL for mail.domain.com it does not load well...
if I add a subdomain with the prefix "mail"
BIND DNS Server = gives an error and stops.

How can I make the information traveling by mail.domain.com travels encrypted by https://

Hi guys,

I'm facing the same issue. When issuing the certificate for domain, mail.domain.com should be also included as an alias.

Anyone, any idea how to fix this?

thanks!