#M365AMA 

“How can you find out, if a person is participating in the teams meeting with 2 devices? What is the best way to prevent it? especially if unauthorized people take part in the meeting on the second device. the unauthorized ones are not visible to others""
Participating in this discussion were:
Christian Buckley, RD+MVP @buckleyplanet
Jonathan Weaver, MVP @j_weaver74
Kirsty McGrath, MVP @KirstyMcGrath13
Hal Hostetler, MVP @TVWizard
Some relevant notes/links shared by the team:
-- You cannot block people from joining a Teams meeting from different devices, but you CAN require admin approval to join, and manually approve or reject secondary connections. Check out this Microsoft Support article: Using the lobby in Microsoft Teams meetings [support.micros...]
-- This is only half of the problem, though. How do you know there is someone else listening in? That's impossible to know, so you can only manually restrict number of device dial ins.
-- Great community discussion on what can and cannot be automated [answers.micros...]