This can be fixed by removing some corrupted files from exim db which will be generated automatically.
Fix
cd /var/spool/exim/db
rm -f retry retry.lockfile
rm -f wait-remote_smtp wait-remote_smtp.lockfile
service exim restart
Some Quick Fixes and Resolutions by Linux Enthusiast
This can be fixed by removing some corrupted files from exim db which will be generated automatically.
Fix
cd /var/spool/exim/db
rm -f retry retry.lockfile
rm -f wait-remote_smtp wait-remote_smtp.lockfile
service exim restart