When mail service is disabled for domain in Plesk, e-mail alias recipient rewriting is still active

E-mail alias recipient rewriting is active when mail service for the domain is disabled in Plesk. Here is the scenario:

• on Plesk mail server, [email protected] is a mail alias for [email protected] mailbox.
• on external mail server, both mailboxes [email protected] and [email protected] are configured as separate mail accounts
• mail is served by external mail server and is disabled at Domains > example.com > Mail Settings 
• attempts to send mail from the mailboxes served by Plesk mail server take local rewrites and mail to [email protected] is delivered to [email protected]

Cause

Plesk bug with ID #PPPM-8110 which will be fixed in future updates.

Resolution

As a workaround:

1. Connect to Plesk server via SSH
2. Remove the information about alias from Postfix database:

   # postmap -d [email protected] /var/spool/postfix/plesk/virtual

   # postmap -d [email protected] /var/spool/postfix/plesk/virtual

If it is required to serve mailboxes by Plesk mail server, the removed entries can be restored for the mailbox:

# plesk repair mail [email protected]