Rejected Status Messages
When there is an issue with an email account, the sender may receive a "Recipient address rejected" status message also known as a "bounce." The following are some common "Recipient address rejected" status messages and their typical meaning:
The recipient has exceeded their storage quota.
The recipient does not exist.
The recipient has been suspended for violating one or more service agreement terms.
The sender that is trying to reach the recipient is sending their message from a network that is known to be the origin of excess spam.
Other errors can be found here.