If you find any of the following errors below in your /var/log/exim_mainlog log file. The fix below should resolve these errors
2013-12-22 03:16:00 Failed to get write lock for /var/spool/exim/db/ratelimit.lockfile: timed out
2013-12-22 03:16:00 H=[18.104.22.168]:13468 temporarily rejected connection in "connect" ACL: ratelimit database not available
To fix these error , the exim cache database on the server needs to be flushed to stop this message.
Run the folllowing command on root:
rm -fv /var/spool/exim/db/*
Then run the following command on root:
service exim restart
If this doesn’t work , then run /scripts/upcp –force on the server and then check exim_mainlog for the changes.