Hello mglincos,
Thanks for posting in the Apple Support Communities.
Is it possible that you signed up to an Acorn subscription (which requires the Acorn TV app for viewing), over adding it as an Apple TV channel? If you follow the steps below, are you seeing it listed as a channel?
Subscribe to Apple TV channels in the Apple TV app - Apple Support
"Watch Apple TV channels in the Apple TV app
- Open the Apple TV app.
- Go to Watch Now.
- Scroll down to My Channels.
- Open the channel to stream content included with your channel subscription in the Apple TV app, without having to download the channel's app.
With Apple TV channels, you can:
For some Apple TV channels, you might be able to sign in to that channel's website or app with the same Apple ID that you use to watch content in the Apple TV app.
If you have trouble accessing a subscription to an Apple TV channel in the Apple TV app, you might need to cancel your subscription on that channel's website or app, then subscribe to the channel again in the Apple TV app."
Best regards.