No surround sound from amp
I have my 4K Apple TV connected to my Lg tv the from the optical out from my tv to my Yamaha surround sound receiver. I seem to only get a stereo signal from the amp. It doesn’t matter what apps or sources I’m using on the Apple TV. The older Apple TV with an optical connection directly to my amp worked fine. My receiver has no HDMI inputs. Any help would be appreciated
Apple TV 4K, tvOS 14