We have been occasionally receiving Undelivered Mail messages when sending invoices through Books:
Bounce Details:
Bounced Address : xxxxxxxxxxxxxxxxxxx
Bounce Reason : uncategorized-bounce
Bounced Time : Sep 13, 2023 03:49 PM GMT
The bounce time matches when the email was originally sent, but the recipients are still receiving the email, but up to almost 2 hours later.
I have analyzed the headers of the mails and see that there is a delay of 106 minutes with sender192.eu.transmail.net (31.186.226.192)
Which matches the delay between the sent email and the received emails.
Why are we getting these notifications IF the email is being sent correctly? Also how are we supposed to know if there really is a problem (and recipients are NOT receiving email) when the server is crying wolf?