When troubleshooting the Exim log file:
tail -f /var/log/exim_mainlog
If you need to restart or rebuild Exim, you can dump your databases
* /etc/exim.conf
* /var/spool/exim/db
Which Exim just rebuilds automatically by issuing the following command via SSH:
rm -fv /var/spool/exim/db/*
Then to start Exim:
/scripts/eximup –force