What mobile app software version and Tesla software package are you running?
Force close your mobile app, clear cache, then restart the app. Ofcourse, make sure the feature is enabled in the car first by going through the security settings. Also, grant the app access to your device's location.
I can confirm that live camview does work on the latest 4.4.2-828 Android Tesla app on a Pixel 6 Pro for an M3 running 2021.44.x.x.
I first started using the live can feature on 202.40.6 on a Samsung S21 Ultra and on iPhone 13 Pro Max. Tesla reps suggests that iOS Mobile apps get the latest Tesla mobile app updates faster than Android. However, I was still able to use it on an older Tesla mobile app version on a Samsung vs the latest release on the iPhone.