Zgemma star 2s got a picture but no sound through hdmi cable

hello, iam in need of a little help please , I have a ZGEMMA STAR 2S it has a good picture but no sound coming through the hdmi cable , the box worked perfect until I unplugged it and set it up in my sons house, I have tried the audio button and changing the digital downmix and checked that it is not on mute . the image is virtusso image extreme I think. any ideas

Thanks

hello, yes I have changed the hdmi cable with a few different ones which I know work

thanks