One or more duplicate records were found in Microsoft Dynamics 365 when saving item from Exchange to Microsoft Dynamics 365

When you track a contact in Microsoft Outlook, the contact is not created in Dynamics 365 but the following alert is logged within the mailbox record:

"One or more duplicate records were found in Microsoft Dynamics 365 when saving item "<Contact Name>" from Exchange to Microsoft Dynamics 365. Do you want to continue and create a duplicate record anyway?

Email Server Error Code: ExchangeSyncDuplicateRecordsError"

If you click Details, the following additional details are displayed:

"T:420
ActivityId: <GUID>
>Exception : Unhandled Exception: Microsoft.Crm.Asynchronous.EmailConnector.ExchangeSyncException: Failed to sync the item to the CRM server, error code : 102    at Microsoft.Crm.Asynchronous.EmailConnector.CrmItem.PerformActionBasedOnUserDecision(Int32 errorCode, SyncItemChangeType changeType)    at Microsoft.Crm.Asynchronous.EmailConnector.CrmItem.UpdateItem()    at Microsoft.Crm.Asynchronous.EmailConnector.ExchangeSyncSteps.WriteToCrmStep.UpdateInCrm(IEnumerable`1 syncItems)"
 

This will occur if duplicate detection is enabled in Dynamics 365 and the contact you tracked in Outlook matches an existing record in Dynamics 365.

For example: Assume you have a duplicate detection rule configured based only on first name and last name and there is an existing contact record in Dynamics 365 named Nancy Anderson. If you have a contact in Outlook with the same name and choose to track that contact in Dynamics 365, the duplicate detection rule will detect a match and won't create the record without confirmation.

Determine if the contact you tracked in Outlook should be created in Microsoft Dynamics 365 or if it is a duplicate of an existing record. If the record should be created in Microsoft Dynamics 365, click the Yes option within the alert.

1. Access your Microsoft Dynamics 365 organization in a web browser.

2. Navigate to Settings and then click Email Configuration.

3. Click Mailboxes.

4. Open your mailbox record and then click the Alerts section on the left side of the page.

5. Locate the alert for the contact record that was not created because a potential duplicate was found.

6. While hovering your mouse over over the alert, you should see a Yes and No option in the upper-right corner. If you want to create the contact in Microsoft Dynamics 365, click Yes.