Shared Mailbox Displaying as Non-Mail-Enabled in ODM (4377398)

In ODM, a shared mailbox may appear as non-mail-enabled, despite being configured as a shared mailbox in the source tenant. This issue may prevent proper migration and mapping within ODM. 

This issue often arises when critical mail-enabled attributes, such as Email and ProxyAddresses, are missing in the source tenant’s Azure Active Directory (AD). Without these attributes, ODM cannot identify the mailbox as mail-enabled.

To resolve this issue, follow these steps:

1. Verify Mail-Enabled Attributes in Azure AD

   • Check that the mailbox in Azure AD includes essential attributes like Email and ProxyAddresses. These attributes are necessary for ODM to detect the mailbox as mail-enabled in a cloud-only environment.

2. Confirm Shared Mailbox Status in Exchange Online

   • Use the Exchange Admin Center (EAC) or PowerShell to verify the mailbox classification in the source tenant.
   • Run the following PowerShell command to confirm that the mailbox is correctly identified as a shared mailbox:
      

     Get-Mailbox -Identity "<mailbox address>" | Format-List RecipientTypeDetails,PrimarySmtpAddress
   • Ensure that RecipientTypeDetails is set to “SharedMailbox.”

3. Check ODM Attribute Requirements

   • Verify that the mailbox meets ODM’s minimum attribute requirements (mail and ProxyAddresses) to be recognized as mail-enabled, even if the mailbox is unlicensed and has minimal storage.

4. Redo Discovery and Matching in ODM

   • Remove the match for the mailbox, re-run the discovery task, and rematch it in ODM. This can refresh ODM’s cache and allow accurate detection.

5. Review ODM Logs for Additional Clues

   • If the mailbox still appears as non-mail-enabled, review ODM’s logs or error reports for any attribute mismatch warnings or other potential insights.