Solved! The sound works when I stream (Netflix/Youtube, etc), but not when watching cable TV.

Jun 11, 2018
This is a recent problem. The only significant change is that I used the sleep timer to turn the TV off when I was watching Netflix. The next time I turned the TV on, there was no sound on cable broadcasts.
Are you using the TV´s speakers?

Which TV is it? brand and model

Is the firmware up to date?

unplug power, press power button for about 30seconds, replug power and test again