Master Dead but PID File exists

Users reported that mail stopped being sent from their server.

Tried to test email functionality from the command line.

# echo "Subject: Testing Sendmail from" | sendmail -v
This is a test
[ctrl + D]

The message wasn’t sent. I tailed the maillog &¬† checked the service¬†status:

# tail -n 500 /var/log/maillog
# service sendmail status
master dead by pid file exists

I checked to see if any Sendmail processes were running and there were several.

 ps -ef | grep sendmail

Stopped the service, deleted the and the lock file and killed all the sendmail processes, then restarted the sendmail service

# service sendmail stop
# rm /var/spool/postfix/pid/
# rm /var/lock/subsys/sendmail
# killall -9 sendmail
# service sendmail start
# service sendmail status

Tailed the logs, resent the email and it was delivered.

# watch tail -n 20 /var/log/maillog