Curious case on one user. Basically this morning he had a couple of conf calls from his iOS and everything was perfect. Now in the afternoon the Meeting, Chat and Calls Tabs are gone in the iOS app so basically he just has the Activity and Teams icons. The app and the OS are up to date and I have tried reinstalling it, but to no effect.
The funny thing is that I logged in the same user on another iOS device which works perfectly for a different user, but with the problematic user's account the problem persists which makes me believe that it might be a policy/configuration problem. And lastly, just to make it even less consistent, the app works perfectly on Android, Windows and Web.