If for whatever reason qmail is started twice or already started shut it down manually...
# qmailctl stop
# ps aux | grep svscan | grep -v grep
root 6398 0.0 0.0 4416 912 pts/0 S 13:32 0:00 svscan
# kill 6398
# ps aux | grep supervise | grep -v grep
root 6400 0.0 0.0 4248 916 pts/0 S 13:32 0:00 supervise send
root 6401 0.0 0.0 4248 880 pts/0 S 13:32 0:00 supervise log
root 6402 0.0 0.0 4248 828 pts/0 S 13:32 0:00 supervise smtp
root 6403 0.0 0.0 4248 916 pts/0 S 13:32 0:00 supervise log
root 6404 0.0 0.0 4248 916 pts/0 S 13:32 0:00 supervise smtps
root 6405 0.0 0.0 4248 824 pts/0 S 13:32 0:00 supervise log
root 6406 0.0 0.0 4248 928 pts/0 S 13:32 0:00 supervise submission
root 6407 0.0 0.0 4248 824 pts/0 S 13:32 0:00 supervise log
# kill 6400 6401 6402 6403 6404 6405 6406 6407
# ps aux | grep tcpserver | grep -v grep
vpopmail 6411 0.0 0.0 6540 1576 pts/0 S 13:32 0:00 /usr/bin/tcpserver -v -R -H -l host.domain.tld -x ... /var/qmail/bin/qmail-smtpd ...
vpopmail 6413 0.0 0.0 4416 860 pts/0 S 13:32 0:00 /usr/bin/tcpserver -v -R -H -l host.domain.tld -x ... /var/qmail/bin/qmail-smtpd ...
vpopmail 6415 0.0 0.0 4416 960 pts/0 S 13:32 0:00 /usr/bin/tcpserver -v -R -H -l host.domain.tld -x ... /var/qmail/bin/qmail-smtpd ...
# kill 6411 6413 6415
# ps aux | grep qmail-send | grep -v grep
qmails 6408 0.0 0.0 8664 976 pts/0 S 13:32 0:00 qmail-send
# kill 6408