Exchange outbound delays (Resolved) Investigating / Notice
3 days

We can confirm that messages are moving as they should. If you received a bounce message it was informing you of the delay which was caused by the Microsoft Exchange routing / DNS. The message is notifying you of the delay and it was delivered between noon and 3PM today. We apologize for the convenience this has caused.

Here is a sample bounce message:

Delivery is delayed to these recipients or groups: (

Subject: Exchange DNS problem causing delays

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 6 days, 18 hours and 40 minutes. You'll be notified if the message can't be delivered by that time.

Diagnostic information for administrators:

Generating server:

Remote Server returned '400 4.4.7 Message delayed'

Original message headers:

Received: from ( by ( with Microsoft SMTP Server

 (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id

 15.1.2176.2; Thu, 12 Oct 2023 09:14:53 -0400

Received: from ([fe80::a9ad:5cb1:b8e1:66c8]) by ([fe80::a9ad:5cb1:b8e1:66c8%5]) with mapi id

 15.01.2176.014; Thu, 12 Oct 2023 09:14:53 -0400 

Please note, this is not related to the delays experienced with Office365/Microsoft365 yesterday. which they have since resolved.

Update 10/12/2023 19:01 PM 3 days

We identified an issue with Microsoft Exchange routing late last night that affected several users in the same user group. Due to an issue with Microsoft updates one of the network controllers was having problems contacting the correct DNS service. This issue caused some emails from some users to keep getting requeued, thus stalling outbound delivery and causing a delay.

We were able to mitigate the issue as of noon today and have confirmed that all messages have been processed and all queues are empty. The messages have been delivered but with a delay.