List hygiene is a best practice in order to maintain a high sending reputation, deliver your messages more quickly and keep high deliverability rates.
Sending messages to inboxes that constantly refuse them affects your reputation as a sender in various ways:
- Mail servers and ISPs monitor the domains and the IP addresses of the sender, keeping track of the sent messages that return a bounce (an error, e.g. recipient not available). If the number of bounces exceeds a predetermined threshold, the sender may be blocked for a certain amount of time or blacklisted. This affects deliverability, so that the number of bounces keeps increasing.
- Receiving a high number of bounces may result in overloaded servers, and higher delivery times as a consequence.
Work in progress. Please bear with us while we update this section