Error message or bounce:
user@emaildestino.com
Domain xxxx.com has exceeded the max defers and failures per hour (10/10 (100%)) allowed. Message discarded.
This problem can be generated when your account (corporate emails or applications) are sending emails to many erroneous addresses or that what is considered spam does not exist and blocks the sending of mail from the domain for a period of 1 hour for reasons of security.
If you receive this message you should:
Verify that a user of your domain is not sending spam or unsolicited mass emails.
Verify that you have not been infected by a PHP malicious script in your Cpanel account.
Verify the general rebounds of the account that are received in the general webmail of the account, you can access that webmail with your main username and password of cpanel by going to www.yourdomain.com/webmail.
If you have not found the cause of the problem, send us a support ticket to perform an additional verification.