A catch-all email mailbox is one that collects all the emails sent to invalid email addresses. For example, if your address is email@example.com, but someone miswrites it and sends an email message to firstname.lastname@example.org, it will still be received in the catch-all mailbox that you have configured. Only one mailbox per domain can have this feature activated and thus you’ll never miss messages because the other party has an out-of-date address or has made a spelling mistake. The downside of setting up a catch-all mailbox is that you may start receiving a lot of unsolicited bulk email messages, but this issue can be resolved by using anti-spam filtering software. It is also crucial to remember that a mailbox with an enabled catch-all functionality cannot forward inbound email messages to a third-party mailbox.