Symptom
The following information level alert appears within a Dynamics 365 mailbox record:
"An internal Microsoft Dynamics 365 error occurred while receiving email through the mailbox [Mailbox Name]. The owner of the associated email server profile [Profile Name] has been notified. The system will try to receive email again later.
Email Server Error Code: IncomingMailboxInternalCrmError"
Cause
This message may appear if Server-Side Synchronization attempted to retrieve emails but encountered an internal error. This is typically a temporary issue and the emails will be retrieved successfully on the next synchronization cycle (typically 15 minutes).
Resolution
If this message does not persist on the next synchronization cycle (typically 15 minutes), this warning can be ignored. If this message persists and email is not being retrieved by Server-Side Synchronization, you can contact Microsoft Support.