19-01-2016, 01:17 PM
has exceeded the max defers and failures per hour (5/5
Domain example.com has exceeded the max defers and failures per hour (5/5 (100%)) allowed
Could it instead be hitting this option in WHM > Exim Configuration Manager?
Ratelimit incoming connnections with only failed recipients [?]
Ratelimit incoming SMTP connections that have only sent to failed recipients five seperate connnection times in the last hour.
The setting is five as listed in the text and the 5/5 for the message you are showing in /var/log/exim_mainlog appears to indicate it might be this setting rather than the defer one in WHM > Tweak Settings that is applying.