Plesk

Let’s Encrypt can not issue certificate for webmail only in Plesk if domain is hosted on another server: An SSL / TLS certificate could not be issued for example.com

Symptoms

Cause

When SSL/TLS Support is enabled in Domains > example.com > Hosting Settings  Let's Encrypt by default tries to issue one certificate that includes example.com and webmail.example.com names.
Since example.com is hosted on another server such certificate can not be issued.

Resolution

Apply one of the following solutions to secure webmail only:

1. Configure Domain as No Hosting

  1. Log in to Plesk.
  2. Go to Domains > example.com > Hosting Settings.
  3. Configure Hosting Type as No web hosting:

    Note: it will remove all files from domain.

2. Disable SSL/TLS Support on Domain

  1. Log in to Plesk.
  2. Go to Domains > example.com > Hosting Settings.
  3. Disable the option SSL/TLS Support: