A catch-all email mailbox receives messages sent to invalid email addresses under the very same domain. For instance, a message sent to the misspelled firstname.lastname@example.org will go to email@example.com in case the catch-all feature has been enabled for the latter. Thus, you can receive messages from colleagues or customers who may have sent a message to your email address with a spelling error or to an outdated one, which they may still have, but you have already deactivated. Only 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 some point you may begin receiving spam messages in the catch-all mailbox and the forwarding restriction implies that the spam will not be redirected to a third-party mailbox.