So we've just started using Teams, mostly for conference calls. Some users though can't actually join the meetings. They see them and when they click Join the screen flashes, almost like a pop up window was trying to appear but then nothing happens. When they click Join Meeting again it goes to the call screen and says Leaving Meeting as if they were joined. The other odd thing is I know when it will happen because in the Team conversation it doesn't show the icon for anybody who is in the meeting already. We're using the Mac version of the Desktop App.