This procedure needs an authorized Plesk server administrator. List the supported panel and mail hostnames, verify their DNS and obtain a trusted certificate covering them. Keep a working administrative session and console recovery route while changing the panel endpoint.

1. Open Tools & Settings > SSL/TLS Certificates. Review the certificates currently assigned to secure Plesk and mail.
2. Request a supported ACME certificate or import a trusted certificate with its matching private key and required intermediate chain. Protect private-key material from public directories and tickets.
3. Assign the intended certificate to the Plesk service using its change control. Check a new browser connection to the supported panel hostname before closing the existing session.
4. Assign the correct certificate to the mail service separately. Domain-specific mail certificates and SNI depend on the installed mail-server capabilities, so confirm the supported configuration rather than assuming a website assignment covers every mail name.
5. Update customer connection guidance if the approved hostname changes and verify the renewal process maintains the service assignments.

Test the panel and the actual IMAP/SMTP TLS connections using their documented ports and TLS modes. Inspect the certificate returned by each service, including its hostname and chain. Confirm a normal mail client sends and receives without a trust exception.

If clients see a mismatch, compare the configured client hostname with the presented certificate. Do not ask users to disable certificate verification. Restore a known valid assignment when necessary, then correct the name or chain. Check after renewal because a newly issued certificate still needs to be used by the relevant service.

• Issuing and renewing a certificate with Plesk SSL It
• Opening Plesk webmail securely
• Changing a mailbox password in Plesk
• Checking local and external mail routing on Plesk for Windows

• Plesk: Securing Plesk And The Mail Server With Ssltls Certificates