Dolby Atmos on Apple TV 4K 64GB not working with Yamaha RX A2040
I am not getting any sound when turn on Dolby Atmos on the Apple TV 4k 64GB. When I turn Atmos off, the sound track reappears. The Apple TV is connected directly to the Yamaha RX A2040 using a new high speed HDMI cable. I am using a 7.1.4 speaker set up. Any suggestions would be greatly appreciated.