Bounce-backs management
A bounced e-mail (or bounce-back) is one that never arrives in the recipient's inbox and is sent back, or bounced back, to the sender with an error message that indicates to the sender that the e-mail was never successfully transmitted. Typically, this happens when you send your mailings using Smtp servers: if an address is non-existent, Smtp server (which has no way of knowing it) will accept the message anyway, but it will be bounced later. There are two main types of bounce-backs: