Issue: Sending domain has exceeded number of failed or deferred messages and is no longer able to send email. This is defined in cPanel tweak settings: “Number of failed or deferred messages a domain may send before protections can be triggered”. When a domain sends the defined number of failed or deferred messages in an hour, and the “Maximum percentage of failed or deferred messages a domain may send per hour” has also been reached, the domain will be temporarily unable to send outgoing mail.
Solution: To immediately fix this issue, reconfigure the following settings more conservatively in cPanel’s tweak settings:
- Maximum percentage of failed or deferred messages a domain may send per hour
- Number of failed or deferred messages a domain may send before protections can be triggered
Then SSH into the server are remove the following file:
/var/cpanel/email_send_limits/max_deferfail_<somedomainname.com>and restart Exim.
That domain will now be able to send email.