No sound on Apple TV 4k

I just bought Apple TV 4k, and there is no sound. I have tried increasing the volume, re-connected the HDMI-cable, switched the ends of the cable, connected it directly to the tv, changed the audio format to stereo, and neither of it works. Audio out is set to HDMI.

I used the same cable for my 3rd gen. Apple TV with no problems. Is it because my tv isn’t a 4k tv?