One of the two local outgoing SMTP servers went offline, but Exchange kept preferring the down server. The downed server was removed from the smart host list and mail was instantly routed via the working outbound node.
Update 05/03/2022 13:28 PM 17 days
We are working on an issue that is affecting outbound mail from some servers. You may receive this notice with the subject "Delivery delayed". We are working on it and expect to resolve the issue shortly, there is no need to resend the message.
This message hasn't been delivered yet. Delivery will continue to be attempted.
The server will keep trying to deliver this message for the next 1 days, 19 hours and 51 minutes. You'll be notified if the message can't be delivered by that time.