Film association Amazon Prime Video

Hi everyone, I have connected Amazon Prime Video and I would like, by putting a film in my list, to understand if it is present in Prime, but I have done various tests and it doesn’t appear.
Today however, for a film that I had put on my list to watch, I received a notification in the app “the film is present on Prime”: I enter Plex, but it tells me that it is not available on any streaming platform.
Where am I wrong?

Are you using a VPN on any of your devices?

No VPN, I’m testing on my home desktop:
ES:

I got the notification I was talking about for a film, but then I see this