Roku setup

[Rr1982]

Hi, I have a new Roku Ultra running through a Pioneer Elite VSX lx 304 avr 7.2.2 system which has Atmos capability. When I set the Roku Audio adjustment to Auto  I get Dolby Atmos but only through the front speakers. I tried everything i know to get all speaker especially the height/Atmos speakers to play in Atmos mode, but the best I get is 5.1.Any advice please? 

[Genryu]

Check the Dolby Enabled Speaker setting on your AV receiver, if you haven't already. Ensure that sound modes (accessed using the * button on your remote during video playback) on the Roku device are set to off. Check the format/s used for audio on your TV. Perhaps rerun the complete setup for your AV as well if none of the above helps. Please do let us know if you find a solution.