Apple TV remote not controlling volume on receiver

Try restarting just the remote, as described in: If the volume buttons on your Apple TV remote aren't working - Apple Support

Verify the Volume Control configuration on Apple TV:

Settings﹥Remotes and Device﹥Volume Control﹥

﹥Auto (default) (use one of the other options if Auto doesn’t work for you)

﹥HDMI (for receivers that support volume control over CEC)

﹥Receiver via IR

﹥TV via IR

﹥Off

﹥Learn New Device (for audio equipment that wants non-standard IR volume control signals)

I am not seeing an option for Receiver via IR.

Then I suppose it is not recognizing any receiver in the setup. Is the Yamaha in between the Apple TV box and the TV in their HDMI connections?

If the issue persists, and unless someone else chimes in with a new idea, I would suggest to contact an expert from the Apple Support staff for further assistance. Contact Apple for support and service (phone numbers) or start your support request online (chat/​email/​callback).

I was having this issue and I chose the HDMI option rather then the custom option I was using before. It basically learned the remote again. It asked me if the tv or soundbar in my case , responded an it did. Mine is no longer custom receiver. I hope this helps!