If you have your own cloud server, you can fix this as follows. For shared/reseller cPanel customers or Managed Customers, please contact our customer care team.
CloudLinux/CentOS cPanel Server
cd /var/spool/exim/db
rm -f retry retry.lockfile
rm -f wait-remote_smtp wait-remote_smtp.lockfile
service exim restart
Alternatively, you can use the following commands:
/usr/sbin/exim_tidydb -t 1d /var/spool/exim retry > /dev/null
/usr/sbin/exim_tidydb -t 1d /var/spool/exim reject > /dev/null
/usr/sbin/exim_tidydb -t 1d /var/spool/exim wait-remote_smtp > /dev/null
/scripts/courierup -- force
/scripts/eximup --force
