Unknown Participant

[RaeCarlton]

While in a meeting all participants hear "An unknown participant is joining/exiting the call". I thought people could only join if invited, called in, or they were given a code. Any idea why someone was able to join and why we were not able to know who it was?

[#2]

@RaeCarlton Yea, same for me, but someone removed him/her 

[#3]

Hello, that is the expected behavior when someone calling in by phone joins or leaves your meeting. (Your admin might have enabled these alerts by default.) It can be controlled in the meeting options as well.

https://support.microsoft.com/en-us/office/change-participant-settings-for-a-teams-meeting-53261366-...