I pay for Apple TV plus every month. Why is the movie asking me to subscribe

I paid for a subscription every month but when I want to watch some movies it's asking me to subscribe

I know this Q is older now. You may have already figured this out by now but Apple TV interface allows you to link other streaming services, etc., and it offers movies and shows from other platforms, so it displays movies and shows from different apps like Prime Video, Max, HULU, Paramount+, Peacock, etc. So if you don't have those subscriptions and you try to watch a movie from those other platforms, you'd have to be a subscriber of those, independently. Otherwise, it will show how much it costs to buy or rent those from those platforms.

There are other movies that might not even be free on those other platform subscriptions. They are simply available for rent or own through the Apple interface but they have nothing to do with Apple at all. Same as if you want to go to Prime Video platform and buy movies not owned by Amazon, you can buy or rent them.

You have to make sure the movies you're wanting to watch FREE are Apple TV+ movies.

Also, some Apple movies are not free for a period of time. Example: Killers of the Flower Moon was in theaters for months and at first, you couldn't even rent or buy it on +. After some time, while it was still in theaters, you could then pay to buy or rent it early on Apple TV+ but now it is finally free to subscribers. It will be the same for Napoleon, Argylle, and other Apple financed theatrical movies.

If the movies you are trying to play are Apple-owned and supposed to be included on your subscription for free but you can't play them, then there must be a technical issue, which the other top post in this thread gives pretty thorough tips how to deal with that.

I paid for a subscription every month but when I want to watch some movies it's asking me to subscribe

Your Apple TV+ subscription gives you access to all of the Apple TV+ catalog, when signed in with the Apple ID that has the subscription linked to it.

There is more content in the Apple TV app, that is not part one Apple TV+, and is thus not included with your subscription. When selecting a movie that is not part of Apple TV+, you may be asked to subscribe/​buy/​rent to an additional service.

For us to be more concise, please specify the title(s).