Loss of some of AppleTV remote functions.

I have a Denon AVR-S750H and a Hisense TV connected through AppleTV. I often switch between speakers and AirPods. Unfortunately, after the last time I used the AirPods and disconnected them, I lost the ability to control volume and mute on the Apple remote. So, now I use the remote to change programs, but have to use the Denon to control the volume and mute. It worked just fine until the last time I disconnected the AirPods. I have tried over and over again to reconnect the remote to the AppleTV, but nothing happens to solve the problem. The remote works right when I bypass the Denon, but I can not find any problems with the Denon's setup and didn't have any problems before. I'm at a loss to figure this out. Anybody have an idea or similar problems?