A catch-all mailbox receives emails sent to non-existent email addresses under the exact same domain. For example, a message sent to the miswritten suport@domain.com will go to support@domain.com if the catch-all feature has been activated for the latter. In this way, you can receive messages from colleagues or customers who may have sent a message to your email address with a typographical error or to an out-of-date one, which they may still have, but you have already deleted. Just one single mailbox per domain name can be a catch-all one and email forwarding cannot be enabled for such a mailbox. The latter is due to the fact that at a certain point you may start receiving spam messages in the catch-all mailbox and the forwarding limitation implies that the spam will not be sent to a 3rd-party mailbox.