For fixing the “T=remote_smtp defer” error message from exim you may need to repair the Exim databases.
First off confirm this is a problem. Query the exim mail queue:
#exim -bp
Pick up a message ID (let’s say 1PVKjs-0008FT-4S) and view it’s log:
#exim -Mvl 1PVKjs-0008FT-4S
If it says something like remote_smtp defer than you may need to repair the exim databases.
/usr/sbin/exim_tidydb -t 1d /var/spool/exim “db”
Replace “db” by the name of the specific dbs on your system. At this time our cPanel servers have these: ratelimit, retry, wait-dk_remote_smtp and wait-remote_smtp. So in a nutshell:
/usr/sbin/exim_tidydb -t 1h /var/spool/exim ratelimit
/usr/sbin/exim_tidydb -t 1h /var/spool/exim retry
/usr/sbin/exim_tidydb -t 1h /var/spool/exim wait-dk_remote_smtp
/usr/sbin/exim_tidydb -t 1h /var/spool/exim wait-remote_smtp
You may want to increase the time: instead of 1h (one hour) you may set 1d (one day) or whatever and you may want to redirect the output to /dev/null (add /dev/null to the end of the above rows).
Alternatively you may want to update exim and courier:
/scripts/courierup — force
/scripts/eximup –force