- Plesk 12.0 for Windows
How to secure mail server in Plesk 12.5 or older and MailEnable version 9.0 or older?
It is possible to apply an SSL certificate to a mail server via Plesk interface starting from Plesk Onyx.
Moreover, SMTP SSL/TLS encryption is available starting from MailEnable version 9.10 only.
It is not supported in Plesk 12.0 and MailEnable 8.53. If securing the mail server is required, the most convenient way is to upgrade Plesk to the latest stable version. Refer to the article below: