Add an option to disable reserved mailnames like root, postmaster, anonymous for domains
If the option What to do with mail for non-existent users set to Forward to address (also known as catch-all address) in Domains > example.com > Mail Settings, then email messages to mailboxes below are not being delivered to the forwarding email address:
anonymous@example.com
mailer-daemon@example.com
drweb@example.com
kluser@example.com
postmaster@example.com
root@example.com
Such mailboxes are present in the file /var/spool/postfix/plesk/virtual.db and mapped to be delivered to @localhost.localdomain:
/usr/sbin/postmap -s /var/spool/postfix/plesk/virtual | grep example.com
anonymous@example.com anonymous@localhost.localdomain
mailer-daemon@example.com mailer-daemon@localhost.localdomain
drweb@example.com drweb@localhost.localdomain
kluser@example.com kluser@localhost.localdomain
postmaster@example.com postmaster@localhost.localdomain
root@example.com root@localhost.localdomain
Please consider to add an option to disable reserved mailnames like root, postmaster, anonymous for domains in Plesk web interface

This is a valid request, so we’ll look into it. There is no ETA at the moment, but we would really appreciate you voting for this request so that we can accurately assess its popularity relative to other features. Thanks in advance!
— rk