Automatic Let's Encrypt Certificate renewal for securing Plesk fails: empty domain name

Symptoms

• Automatic Let's Encrypt Certificate renewal for securing Plesk fails and following error message can be found in /var/log/plesk/panel.log file:

  # egrep "ILLEGAL_ARGUMENT" /var/log/plesk/panel.log
  ...
  ERR [extension/letsencrypt] Failed to renew Panel certificate: idn_to_ascii: empty domain name: U_ILLEGAL_ARGUMENT_ERROR.
  ...

• Renewing manually Let's Encrypt Certificate for securing Plesk going to Tools & Settings > SSL/TLS Certificates > Let's Encrypt > Renew works successfully.

Cause

Let's Encrypt extension bug with ID EXTLETSENC-573. A fix will become available in upcoming Let's Encrypt extension updates.

Resolution

As a workaround, issue manually a Let's Encrypt Certificate for securing Plesk according to the instructions provided in following KB articles:

• How to secure Plesk login page URL with SSL certificate
• How to secure Plesk and mail server with Let's Encrypt certificate via CLI?