@Chris Collins I hope you are doing well,
Try this please this guide tell us if it work for you...
To make your @<TeamName> mention work, you need to change the team's notification delivery preference so that ADO knows to expand the membership and email everyone individually.
- Navigate to Project Settings (the gear icon in the bottom left corner).
Under the General section, select Teams.
Click on the specific Team you are trying to tag.
Click on the Notifications link/tab for that team.
Click on Delivery Settings near the top of the page.
Change the delivery preference to Deliver to individual members.
Click Save.
Once this is updated, tagging the Team in a work item will successfully trigger an email to all licensed users within that team.
If you do not want to create an ADO Team and prefer to use a standard group, you must use a mail-enabled security group or Microsoft 365 group originating from your Microsoft Entra ID (Azure AD).
If the AD security group you mentioned in your initial tests was not mail-enabled (meaning it does not have a valid email address in Exchange), ADO cannot send an email to it.
If you sync a mail-enabled group into ADO, tagging that group's name will push the notification to the group's email address, and your Exchange server will handle distributing it to the individual members.
Try adjusting the Delivery Settings on your test Team first. That is the most reliable, native way to achieve what you are trying to do without having to request new mail-enabled groups from your IT department!Here is how you can configure a Team or a Group to successfully notify all members when tagged.
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