"Maximum limits for failed / deferred mail:
Domain sudominio.com has exceeded the max defers and failures per hour (5/5 (?%)) allowed. Message discarded."
The "exceeded the max defers and failures per hour" message is a cPanel message that outgoing email is being held on the server until the number of emails that have failed or been deferred is below the email threshold.
This tool tracks and limits outgoing mail based on the maximum percentage of failed or deferred messages that a domain can send per hour. The system examines outgoing mail in the last hour to determine if the domain has exceeded the limit.
When a domain exceeds the limit, it cannot send emails until enough time has elapsed for the domain to be below the limit again.
Our shared servers are configured to a 60% failure rate. The tool is coded to keep track of deferred / failed mails after 5/5 has been reached within the last hour.
Once the 5/5 limit and 60% failure rate have been reached, ALL emails for the domain will fail until the rate drops below 60%.
This will happen 60 minutes after the first detected fault.
