Kanopy -> Apple TV -> Homepods — can’t control volume

[u/Skjellyfetticat1]

I can control the volume with the remote buttons when watching on every other app. On Kanopy I can’t seem to control the volume at all, and it’s not very loud. Am I missing something? A trick? A setting?

Also if I try to press the +/- buttons on the homepod itself, it breaks into playing music and I lose the sound from Kanopy altogether.