A catch-all email mailbox receives emails sent to nonexistent email addresses under the same domain name. For example, a message sent to the mistyped firstname.lastname@example.org will go to email@example.com in case the catch-all feature has been activated for the latter. In this way, you can get messages from colleagues or clients who may have sent a message to your email address with a spelling error or to an obsolete one, which they may still have, but you have already deleted. Only one single mailbox per domain name can be a catch-all one and email forwarding cannot be enabled for such a mailbox. This is so because of the fact that at a certain moment you may begin receiving spam emails in the catch-all mailbox and the forwarding restriction means that the spam will not be delivered to a 3rd-party mailbox.