Being you're using Linux, I suggest you check the folder permissions for your media, the ownership has to be jellyfin and the group has to be jellyfin with 775 permissions on all folders inside you media folder.
Windows don't really care about permissions, as long as the permissions are not read only and hidden, but when you migrate to Linux, Linux is all about permissions, I use a Dell PowerEdge T710 dedicated server running headless Ubuntu server OS, and I have an HD dedicated to media files, which has this structure:
/mnt/shows
/mnt/movies
Then I have:
/mnt/shows/<show name>/season 1 .. 2 .. 3 .. 4 etc
/mnt/movies/<all the movies I want put in here>
Then I had to use this:
sudo groupadd jellyfin
sudo usermod -aG jellyfin jellyfin
Then navigate to your media folder's root, IE, in my case it's /mnt/movies, then I use sudo chown -R jellyfish:jellyfish /mnt/movies (or whatever your media folder is), then use sudo chmod -R 775 /mnt/movies (or whatever your media folder is).
If you have a single folder called 'media', then inside that you have shows, movies, etc etc, then navigate to one folder before 'media', IE /mnt/media then inside that you have all the folders for shows, movies, etc etc, in that case you would use:
sudo chown -R jellyfin:jellyfin /mnt/media
sudo chmod -R 775 /mnt/media
This will give jellyfin read/write/execute permissions.
This is where Linux outsmarts windows, in that Linux heavily relies on permissions, if you or the software you're running don't have permission to do something, then Linux won't let it happen.
All this is performed in an Ubuntu terminal console.
Windows don't really care about permissions, as long as the permissions are not read only and hidden, but when you migrate to Linux, Linux is all about permissions, I use a Dell PowerEdge T710 dedicated server running headless Ubuntu server OS, and I have an HD dedicated to media files, which has this structure:
/mnt/shows
/mnt/movies
Then I have:
/mnt/shows/<show name>/season 1 .. 2 .. 3 .. 4 etc
/mnt/movies/<all the movies I want put in here>
Then I had to use this:
sudo groupadd jellyfin
sudo usermod -aG jellyfin jellyfin
Then navigate to your media folder's root, IE, in my case it's /mnt/movies, then I use sudo chown -R jellyfish:jellyfish /mnt/movies (or whatever your media folder is), then use sudo chmod -R 775 /mnt/movies (or whatever your media folder is).
If you have a single folder called 'media', then inside that you have shows, movies, etc etc, then navigate to one folder before 'media', IE /mnt/media then inside that you have all the folders for shows, movies, etc etc, in that case you would use:
sudo chown -R jellyfin:jellyfin /mnt/media
sudo chmod -R 775 /mnt/media
This will give jellyfin read/write/execute permissions.
This is where Linux outsmarts windows, in that Linux heavily relies on permissions, if you or the software you're running don't have permission to do something, then Linux won't let it happen.
All this is performed in an Ubuntu terminal console.