The add-in hasn't appeared after deploying it

You've added MailTail from the Microsoft 365 admin centre, but it isn't appearing in Outlook for you or your users. This is almost always Microsoft's own rollout timing rather than a problem with the add-in itself. Work through the list.

1. Give Microsoft's rollout time

When an administrator deploys an add-in through the Microsoft 365 admin centre (Integrated Apps / centralized deployment):

• A new deployment can take up to 24 hours to appear for all assigned users.
• Later updates can take up to 72 hours to reach everyone.

This is Microsoft's timing and applies to any add-in, not just MailTail. It usually appears sooner, especially after a restart.

2. Restart Outlook

Add-in changes apply the next time the Outlook app starts. Close Outlook completely (check the system tray by the clock on Windows) and reopen it.

3. Check who it was assigned to

In the Microsoft 365 admin centre, under Settings then Integrated apps, open the MailTail deployment and confirm the user is in scope: either the whole organisation, or a group they belong to. If it was deployed to "just me" or a test group, other users won't see it until you widen the assignment.

4. Check the right Outlook client

The add-in appears in Outlook on the web, New and Classic Outlook on Windows, and Outlook on Mac. If a user only checks one client, try another. The button appears on the ribbon, or in the … (More actions) / Apps menu when composing a message.

5. Confirm the account type

MailTail works with Microsoft 365 (Exchange Online) mailboxes. A personal Outlook.com account or an on-premises-only mailbox won't show organisation-deployed add-ins the same way. See Requirements and supported environments.