Used to have this same problem with older firmware versions. Only way for me to recover was:
1) turn off mobile access
2) park car, roll down windows (SoCal Heat)
3) Close all doors, power down car.
4) Wait 3-4min after power down. Touch nothing.
5) Open driver door to power the car back up.
6) After it is powered back up, Hold down brake pedal (keep holding it)
7) Hold two scroll wheels until MCU powers down and you see the Tesla logo.
8) Release Brake and scroll wheels and let everything power back up.
9) Once the car showed connected again (LTE or WiFi) then test it out and see if it is working now.
After the above it would usually clear whatever it was and start working (don’t forget to re-enable mobile access).