Not sure if anyone has experienced same issue like me.
1. I joined a meeting from PC, then see join button on my mobile, and join from phone same time, no issues.
2. without join a meeting from PC first, trying to join from moblie, don't see the join the button on mobile. Problem
3. without start a meeting from PC, however, I can start a meeting from mobile app, no issues
btw, mobile is iphone