To help stop spam, we have started monitoring the amount of emails that each account sends out which result in bounce backs. If our system detects that 10% or more of the emails being sent out from an account are resulting in defers or failures (bounce backs), the system will prevent the account from sending out any further emails for up to one calendar hour.
In other words, if 10% or more of the emails sent from your account within a one hour period bounce back, the system will prevent you from sending out any further emails for up to one hour. You will know this has occurred when you get an immediate bounce back that says:
This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:
Domain your-domain.com.au has exceeded the max defers and failures per hour (5/5 (50%)) allowed. Message discarded.
There are generally two circumstances under which this will occur:
- You are sending out mass emails and some of the addresses in your mailing list are inactive
- Your account has been hacked and is being used to send out spam by a malicious user
What should you do to prevent/fix this?
If you are sending out mass emails
If you are sending out mass emails and this has occurred, it most likely means that many of your subscribers are no longer using the email addresses that they subscribed with. You will need to clean up your mailing list and stop sending these inactive accounts your emails. Within cPanel there is a tool called Email Trace which can assist you in cleaning up your mailing list.
- Log into cPanel
- Click on the Email Trace icon
- Leave the Recipient Mail field blank and Click [Run Report]
- Information about all the emails sent out from your account will be displayed. Use the information provided to determine which email addresses you should stop sending emails out to and remove them from your mailing lists
If you are not sending out mass emails
If you are not sending out mass emails but are getting the "max defers and failures per hour" bounce back message, it might mean that your account has been hacked. Before you panic, follow the above steps 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 the problem continues, we recommend you read through the below support articles relating to hacked websites then contact us if you require further assistance.