Delete the queue

$ cd /var/qmail/queue (or whereever the queue is)
$ /usr/bin/find intd todo local remote mess info bounce -type f -print |xargs rm

Bounce mail off of the queue by subject

grep -ir "CENTRAL BANK OF NIGERIA" * | cut -d ':' -f 1 | xargs touch -t 200001010000

To remove (stop qmail-send first)
find . -type f -print0 | xargs -0 grep "CENTRAL BANK OF NIGERIA" | cut -d ':' -f 1 | xargs rm

If qmail-remove is available

qmail-remove -r -p "CENTRAL BANK OF NIGERIA"

To block emails from a specific addresses. add the address (such as @domain.com or user@domain.com) to
/var/qmail/control/badmailfrom

Force to run: go to /var/services/qmail-smtp and /var/services/qmail-send and run

./run > /dev/null/ && bg

force qmail to send and empty queue

killall -14 qmail-send

Allow relay (tcp.smtp)

after modifying /etc/tcp.smtp run the following

Note that /etc/tcp.tmp shouldn't exist

Reading qmail logs which are in TAI64N: