Internal Email delayed with Office 365

Question

I have noticed that internal emails are delayed, sometimes by a few hours. There are all internal emails, exclusively Exchange Online and using the updated Office 365 applications.

We have checked Outlook online and the messages don't appear their or push to the phone either.

Message trace in EAC show that they are, Received, Submit, and Delivered when they are sent.

they don't appear for 3-6 hours. this is for internal emails only, all external emails are being received when expected.

Answer 1

Hi @PhilD19 ,

When we did actually perform an Outlook on the web search we were able to find the emails. We found that the emails were being routed by a rule created on OWA to route to the RSS folder. We have taken appropriate steps to mitigate this when it was found, I will start a support case to do some further investigation on this and what it all entailed.

Glad to see that you've found the culprit and appreciated it for sharing the findings and the current status of this issue. This can definitely help others experiencing the same thing easily reference this! And should you get more information from the support case you opened, it'd also be great if you can share it here at your convenience :-)

By the way, since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others", I'll repost your reply in case you'd like to "Accept" the answer : )

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[Internal Email delayed with Office 365]

Issue Symptom:

Internal emails are delayed, sometimes by a few hours. There are all internal emails, exclusively Exchange Online and using the updated Office 365 applications.
Message trace in EAC show that they are, Received, Submit, and Delivered when they are sent.
they don't appear for 3-6 hours. this is for internal emails only, all external emails are being received when expected.

Current solution:

"We found that the emails were being routed by a rule created on OWA to route to the RSS folder. We have taken appropriate steps to mitigate this when it was found."

Answer 2

Hi @PhilD19 ,

I have noticed that internal emails are delayed, sometimes by a few hours.

When did you stat notice this issue?
Does this affect all internal emails or only some particular mails are delayed?

If only some of the mails are delayed, I'd suggest checking if the affected mails have anything in common, such as sent by a specific user, or have large size, etc.

We have checked Outlook online and the messages don't appear their or push to the phone either.

Have you tried searching in Outlook on the web using some keywords of a missing message and see if it can be found within the mailbox?

Besides, I'd recommend checking service health (https://portal.office.com/Adminportal/Home/#/servicehealth) via your Microsoft 365 admin center to see if there's any potentially relevant service degradation which may lead to the message delay.

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