Had an issue today in trying to deliver an email to a mailbox on my hosting provider as they were subject to a DoS attack. After the issue was resolved, I still had a mail in my AMS queue failing to be delivered.
They have advised that their configuration expects that upon failures, sending mail servers should wait for longer intervals on each subsequent attempt.
My AMS is currently configured to retry on 15 minute intervals for up to 7 days.
They have suggested that a fixed retry interval is not 'best practice', but it seems to be the only option within AMS.
Any thoughts on this? I've cleared the mail from the outgoing queue for now and will leave until tomorrow to retry.