Devices that use Android TV or Google TV (including Sony TVs) or Fire OS as operating system are not supported for direct financial transactions through the Apple TV app at this time (except for subscribing to Apple TV+ only on Fire TV in the US). Those devices do have the full Apple TV app that can access the Library, so that past purchases are accessible, but new purchases will have to be done on a different device (e.g. iPhone) that doesn’t have this limitation.
I don’t think it is about the cable provider.
Get the Apple TV app on your smart TV or streaming device - Apple Support
2. In the US, you can subscribe to Apple TV on Amazon Fire TV and Prime Video, but you can't purchase other content from the Apple TV app. On Amazon Fire TV (in other regions), Android TV, and Sony TV devices, you can't purchase content from the Apple TV app. You can buy, rent, or subscribe on another supported device and then watch in the Apple TV app on your Amazon Fire TV, Android TV, or Sony TV device.