Relevant Products: Exclaimer Cloud - Signatures for Office 365
Scenario
When an email is sent from a shared mailbox, a signature is not added to the received message.
Reason
This occurs in hybrid environments where a local user account's mailbox has been converted to a shared mailbox using the Microsoft 365 admin center. If the mailbox is shared and the Microsoft 365 license removed, then their Active Directory account is disabled.
To generate signatures, Exclaimer Cloud aggregates data from the Active Directory and from Microsoft 365 however, data for disabled users is not aggregated. Also, disabled users cannot be selected when choosing whose signatures should be applied to, so no signature is applied.
Microsoft 365 accounts that have been converted to a shared mailbox must not be blocked from signing in, as this will mark the account as being disabled.
Resolution
To resolve this issue, you can either do one of the following:
- Enable the user account in Active Directory.
Once enabled and synchronized with Azure - and after your Azure data has subsequently been synchronized to Exclaimer Cloud - a signature will be applied to emails sent from the shared mailbox (according to your signature settings in Exclaimer Cloud).
Note: For more information, see How to Create or Convert Shared Mailboxes in Office 365. - Create a brand new shared mailbox in Microsoft 365 (instead of converting an existing Active Directory user's mailbox).
Shared mailboxes created in Microsoft 365 do not generate a user account in the Active Directory and do not require a Microsoft 365 license.