I signed up for apple tv on my Amazon fire tv but cannot watch anything but free episodes on it.
How can I start watching movies on my fire tv with the apple TV app?
Verify that you are signed in with a complete and validated Apple ID account.
You can’t subscribe to or make purchases for Apple services on Fire TV devices [1]. There is currently no agreement between Apple and Amazon for each other’s in-app purchases. You will have to do the subscribing or purchasing part on a different device.