Couldn't Find a Movie available on Apple TV

are you talking about appletv+ apples steaming service with only apple produced material?

or if you are talking about the third party content apple let people purchase and rent using their itunes store then

what material is available differ from region to region so it might not be available where you are

if you post what movie it was then the rest of us can see if it's available where we live.

I think answering can be a bit more effective with some additional information:

1. Did you search it in the Apple TV app on Windows, or on some other device (if so, which model)? Some devices have a specialized edition of the app, without Store for buy/​rent titles.
2. Can you disclose the title of the movie that you wanted to see?
3. Which site said that this title was available on Apple TV?
4. In which country or country-like region are you searching? Some titles are available in one country, but not in another.