Plesk Migrator shows warning: Cannot manage webmail settings: domain has subdomain 'webmail'

Symptoms

• Plesk Migrator shows the following warning after subscription migration:

  PLESK_INFO: Plesk restore report problem:
  Execution of /usr/local/psa/admin/plib/api-cli/domain_pref.php --update example.com -webmail -ignore-nonexistent-options failed with return code 1.
  Stderr is
  An error occurred while updating domain settings: Cannot manage webmail settings: domain has subdomain 'webmail'

• The domain with the name webmail.example.com exists on the source server.

Cause

It is expected behavior when the subscription on the source server has a domain with the webmail. prefix.

Plesk automatically creates a DNS record webmail.example.com for the domain. So it is no needed to create a subdomain with the webmail. prefix.

Resolution

1. Log in to the source panel.
2. Remove the domain webmail.example.com.
3. Log in to Plesk on the target server
4. Remove the failed subscription.
5. Re-migrate the subscription once again.