Somebody had success with no sound from their stick by swapping the HDMI port connected to the stick and going into their TV settings and playing around with the HDMI CEC feature.
Bit of a long shot but might be worth a try.
What make and model of TV is it connected to?
If this is in turn connected to a soundbar or AV amplifier, disconnect that for the moment, to see if you can get the sound from the TV on its own.
Let us know if this works or not, and we can then consider the next step to get the whole setup working.