The answer to this depends on how the message is bouncing. If it is a so-called "Hard Bounce", where the mail service at the destination domain actually reports that there is no such address, then the system immediately stops sending the email, and a bounce message is returned.

A 'retry' of the email send is done when communication between mail servers cannot be established, resulting in a "Soft Bounce". This can occur for many reasons and is very common on the Internet today. For example, if the AOL mail servers are busy, the mailer may need to retry sending the message several times before it is accepted. The ability to retry delivery of an email is a necessary and required process for the successful operation of a mailer.

While it might be "best practice" to attempt delivery on an email message at least 4 or 5 times, the eNews Builder mailer is configured to do this much more than that. Our mailer will attempt delivery every 5 minutes for up to 72 to 108 hours for a possible minimum total of 864 tries, all the way up to 1296 tries. If at the end of this process, the mailer is not able to successfully connect to the mail server destination, it will return the outgoing message as a "bounce" that appears in the bounce manager under the "Unknown" category.

Every email that ends up in the bounce manager has gone through the same process.