If an email bounces, we will retry for up to 72 hours. If the email is unable to be delivered within the last 72 hours, it will expire and be marked as Bounced - Expired.
Bounced emails are commonly due to SMTP 4.X.X errors or SMTP 5.X.X errors, which cause an email to be undeliverable:
If you have a question that needs an answer, please contact support. Otherwise, please open an issue in our GitHub! Thanks for helping us improve our docs!