Apple 4K Dolby Atmos not working with my Pioneer Elite SC85 receiver

I cannot get Dolby Atmos to show as an option on my Apple TV 4K. Updated software on both devices, quick start turned on, Atmos works fine with my other devices including my blu-ray player and automatically recognizes the format. Read several forums but have not found a solution. Using 7.1.2 setup with my Pioneer Elite SC85 receiver