Scenario
While managing signature rules, you notice that the groups you know exist in Microsoft 365 do not appear within the search results of the Members of this group option.
Example of the Members of this group option.
Reason
When managing signature rules, you can only add mail-enabled security and distribution groups to the senders.
Resolution
- Re-create any non mail-enabled groups as distribution or mail-enabled security groups.
If the group is mail-enabled but still not visible, perform a manual data synchronization.
If this does not resolve the issue, raise a Support ticket.