Securing Plesk and the Mail Server With SSL/TLS Certificates – Securing Plesk and the Mail Server With a Self-Signed Certificate

As we explained earlier, it is always preferable to use an SSL/TLS certificate from
Let’s Encrypt or a paid SSL/TLS certificate from a different certificate
authority.
However, you may want to secure Plesk and the mail server with a
self-signed SSL/TLS certificate, if, for example,
the certificate issued by a certificate authority has expired.

To secure Plesk and the mail server with a self-signed certificate:

1. Go to Tools & Settings > SSL/TLS Certificates (under
   “Security”) and click the + Add button.
2. Fill in the fields marked with the asterisk. Pay particular attention
   to the following fields:
   • “Certificate name”. Give the certificate a recognizable name so
     you can tell it apart from other certificates in the server
     repository.
   • “Bits”. The more bits, the more secure the certificate. We
     recommend using the default value (4096).
   • “Domain name”. Make sure that the name in this field matches the
     server hostname.
3. If all the provided information is accurate, click Self-Signed.
   Plesk will generate a self-signed certificate and display it in “List
   of certificates in server pool”.
4. To secure Plesk, click the [Change] link next to “Certificate for
   securing Plesk”. Select the certificate generated during the previous
   step from the drop-down list, and then click OK.
5. To secure the mail server, repeat the previous step for “Certificate
   for securing mail”.