Can't view Microsoft 365 IRM-encrypted message for dynamic distribution group

  • Article
  • Applies to:
    Microsoft 365 Business, Outlook

Original KB number:   4459264

Symptoms

Assume that you send an email to a Microsoft Exchange Online dynamic distribution group that has an Azure Information Protection IRM-protected template applied, such as Do Not Forward. When the recipient tries to open the email, they are redirected to Outlook on the web. Outlook on the web displays a button to read the message, but selecting the button does not work, and the recipient gets caught in an infinite loop without being able to view the message. Emails sent to recipients and a distribution group work fine.

Cause

This behavior is by design. IRM encryption doesn't support dynamic distribution groups.

Resolution

Use a distribution group as the recipient for IRM-protected messages instead of using a dynamic distribution group.