Spamphibian Gateway will immediately attempt to deliver bounce messages to the sender. Bounce messages can be the result of a failed message delivery or the "bounce" filter action. If Spamphibian Gateway is unable to deliver a bounce message it will be placed into the "Retry Queue". Bounce messages will contain a "X-Spamphibian-Bounce-Reason:" header.

Spamphibian Gateway will attempt to deliver the bounce message every 5 minutes for 72 hours. If Spamphibian Gateway is unable to deliver the bounce message after 72 hours, the bounce message will be removed from the "Retry Queue". To determine if any bounced messages have been removed from the "Retry Queue", check your "Log" view.