Jellyfin does not detect all movies

[Pascal]

Hi  
I did not find any solution for my problem.
Jellyfin does not detect all my movies.

I am using best practice names for all of my movies and folders like: 
Media/Movies/Movie (2021) [imdbid-tt12801262]/Movie (2021) [imdbid-tt12801262].mkv or .mp4
https://jellyfin.org/docs/general/server/media/movies/

I tried Plex just for fun and it detects every movie.
Is there anything I can do to find the missing movies and the reason why they are missing?