Why don't I hear any sound/audio on one or more channels with my CM-7003 Digital to Analog Converter Box?

Why does one of my channels have ‘no audio’/’no sound’ on one channel?

1. CM-7003, No Audio on some channels.
2. Press the Audio button on the remote.
3. Navigate to "Undefined" audio and press 'OK' button.
4. Change the Left/Right settings and then back to Left/Right.
5. Press ok. Test all channels.