Apple TV: IPhone app vs Fire TV app

I subscribed to Apple TV on my iPhone. I then downloaded the Apple TV app onto my Amazon Firestick so I can stream on my larger tv. However, there are movies and shows that are available for me to watch on my iPhone but if I try to access them on the Firestick app, it says “how to watch” and says I have to subscribe to a certain channel. For example, on my iPhone, if I click on A Simple Favor, the play button appears and I can watch it. If I click on the same movie on the Apple TV Firestick app, it says “how to watch” and won’t let me play it. And, yes, I am signed in. Any suggestions?