2023/07/05 @ 07:45
During the early hours of today mailRelay users with a static IP for sending assigned from our pool may have encountered repeated deferral of mail acceptance due to a name resolution related issue. During this time a 421 error will have been seen, instructing the remote party to retry later.
Appropriately configured senders will retry and therefore no further action is required. If you do not automatically retry as per standards and conventions the email will need to be resent if you encountered a 421.
Adjustments have been made to how we implement name resolution and monitor it from a mailRelay with Static IP perspective to prevent a reoccurrence.