SOLVED: Playback failed due to a fatal player error.

[Quinterly]

So, I've confirmed all the Jellyfin permissions are right. It's actually ffmpeg that doesn't appear to have permission. From Jellyfin's log:

Code:

MediaBrowser.MediaEncoding.Transcoding.TranscodeManager: FFmpeg exited with code 1

And, as above, ffmpeg's log is showing:

Code:

file:F:\Movies\MMM (2023)\MMM (2023) WEBDL-1080p.mkv: Permission denied

Not sure how to get ffmpeg permissions corrected?