You may set the over-quota auto-responder text. When email is sent to a mailbox that is over-quota, the message you set will be automatically sent to the message's sender.
To set the over-quota auto-responder
Click the Set Over - Quota Auto - Responder here link.
Enter or add the auto-responder text in the given text area.
Click Save to save your changes, or click Cancel to make no changes and return to the Mail Manager homepage.