Failed to renew Lets Encrypt certificate: One of the certificates you are going to delete is used for securing Plesk

Symptoms

• Unable to renew Lets Encrypt certificate in Home > Domains > example.com > SSL/TLS Certificates > Reissue Certificate with the next error:

  PLESK_ERROR: Error: Let's Encrypt SSL/TLS certificate installation failed:
  Remove certificate failure: One of the certificates you are going to delete is used for securing Plesk.

• Plesk (and mail server) secured in Home > Tools & Settings > SSL/TLS Certificates with the certificate issued for example.com (e.g. the certificate name is Lets Encrypt example.com)

• The server hostname differs from example.com

Cause

Plesk (and mail server) is secured by the same certificate as the domain example.com. This certificate cannot be deleted.

Resolution

As the best practice in general, it is better to use separate certificates to secure Plesk with the mail server and domain.

Secure Plesk (and mail server) with a unique certificate: