mailq | grep MAILER-DAEMON | awk '{print $1}' | xargs -n 1 /usr/local/postfix/sbin/postsuper -d
Mailq format
4F12F2AC5A 322 Wed May 21 13:11:39 root@solman.toon-net.local
(delivery temporarily suspended: connect to example.org[208.77.188.166]: Connection timed out)
user@example.org
root@solman.toon-net.local = Sending email address user@example.org = Recipient