copy folder and all fiels from
/var/lib/pmg/templates
to
/etc/pmg/templates
Edit the files: /etc/pmg/templates/main.cf.in
at the smtpd_sender_restrictions part,
add below content:
check_sender_access regexp:/etc/postfix/Blocked_Sender_Domain
Edit the file: /etc/postfix/Blocked_Sender_Domain...