An unknown error occurred while receiving email through the mailbox

I’ve noticed in all 3 of our environments that under the Alerts section of all of our Mailboxes, we get this error. It happens all hours of the day. It also happens even when we do not have an incoming email. We have a process setup to review the mailboxes in Outlook, and when an email is found create a Case. We are trying to find out what is causing these Alerts, but I can’t find anything on the web for it. Does anyone else have these or can you point me to how we can fix it?

An unknown error occurred while receiving email through the mailbox . The owner of the associated email server profile Microsoft Exchange Online has been notified. The system will try to receive email again later.
Email Server Error Code: Exchange server returned UnknownIncomingEmailIntegrationError NoError exception.

@tsilver - Could you go to the “General” screen and look at how you have configured the mailbox? Specifically the Configuration Test Results and the Synchronization Method sections. This is how synchronization method looks.

I also wonder since your mailbox says dev sandbox. Is this a production or development environment?

Here’s a support article from Microsoft. Apparently it’s a known issue and can be ignored if the email is working.

I took the sample from our Sandbox (Dev testing instance) as that is where we are troubleshooting from. This issue happens in our Sandbox (User Testing) and Production environments. We have emails going out and coming in all day long, and we don’t seem to have issues with emails not getting to where they should be going. Looks like Jacob found an article. (I’ve been searching for weeks and hadn’t found that one.)

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Thank you! I’ve been searching using all forms of the error and had not found this particular site. Sounds like we get to keep viewing these as our Health Dashboard seems to be good and our email traffic in and out of Dynamics is working.

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