Yesterday one of my colleagues logged into a different tenant using the Microsoft Teams App. All worked really well!

Today during our daily stand up call that same colleague joined our Video call and he was marked as Unknown User see screenshot below:

How is it possible that an account that doesn’t have access to a team, can access our meeting? Just by having the url of the meeting anybody in the world has access to meetings.

I’m still investigating the issue but this doesn’t look right to me.