When viewing Alerts for a mailbox in Dynamics 365, you see the following warning:
"Appointments, contacts, and tasks for the mailbox [Mailbox Name] couldn't be synchronized. The owner of the associated email server profile [Profile Name] has been notified. The system will try again later."
The following additional details are also included:
"Error : Exchange Error Code: ErrorIrresolvableConflict
Exchange Error Message : The operation can't be performed because the item is out of date. Reload the item and try again. Exchange Error Details: System.Collections.Generic.Dictionary`2[System.String,System.String]"