When you first install Mio, it's only installed at the team level.
However, an administrator may authenticate their account and allow the Mio app to access more permissions.
This means that any Microsoft Teams user in any team will be able to use the app to create channels and chat with external contacts.
You may also see this message when trying to create a universal channel from the Mio app, or when trying to start a direct chat.
If you're an administrator, go ahead and select "Yes, I'm an admin" to authenticate admin scopes for the Mio app.
You can review this list of all scopes requested by the Mio app.
If you have more questions about setting up Mio on Microsoft Teams, please contact us using the chat bot in the bottom right corner.