The Chromecast issue on iOS and Android has been resolved as of 12/14/2022. 

If you are still unable to use Chromecast, please delete the app, restart the device, and reinstall the app, making sure to accept/allow all related permissions (Bluetooth, Nearby Devices, etc.). Make sure the device you are casting to is connected to the same network. You should now be able to cast from the video player Chromecast button and from the main menu Chromecast button.