To prevent your account from being unwittingly used to send spam, and maintain the good reputation of our email service for all customers, we have implemented a system to monitor the number of emails which fail to send. A number of failed email sending attempts in a short period of time can be indicative of spam as emails are sent to a randomly generated list of addresses.
If our system detects that 50% or more of the emails being sent out from an account within any continuous 60 minute period result in defers or failures, the account will be prevented from sending emails for 60 minutes. Attempts to send emails during this period will result in an instant bounce back with the error message Domain xxx has exceeded the max defers and failures per hour allowed. The email message will not be sent and will not automatically be re-sent later.
Typically there are two situations under which you might encounter this error:
- You are sending out mass emails (eg. mailing list) and some of the addresses in your mailing list are invalid,
- Unauthorised access has been gained to your account and is being used to send out spam by a malicious user.
If you are sending mass emails such as to a mailing list, it most likely indicates some of your subscribers are no longer using the email addresses they subscribed with. You will need to clean up your mailing list and stop sending to these recipients. The "Email Trace" page within cPanel to check which emails might be failing for this reason so they can be removed.
The documentation for this page is located here.
If you are not sending out mass emails, it might mean that your account has been compromised. To confirm this, use the Email Trace function to see what emails have been sent out from your account recently. If you do not recognise many of the email addresses in the Email Trace report you should update the password for the email account that is being used to send out these emails.
If you'd like further assistance troubleshooting this bounce message, please don't hesitate to open a support ticket with the technical support department. Please include a copy of the email you were trying to send and the bounce message you received back