A catch-all mailbox is one that captures all the emails sent to invalid addresses. For example, if your address is email@example.com, but someone misspells it and sends an email to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have created. Just one single mailbox per domain can have this feature enabled and thus you will never miss messages because the other party has an obsolete address or has made a mistake. The disadvantage of configuring a catch-all mailbox is that you may start receiving a lot of unsolicited bulk emails, but this issue can be resolved using an anti-spam protection solution. It’s also essential to bear in mind that a mailbox with an enabled catch-all feature cannot forward inbound email messages to a 3rd-party email address.