Subtitle Unbreakable.2000.1080p.bluray.x264.dts... [ HIGH-QUALITY ]

For your media player to detect the subtitles automatically, the filenames must match . Naming and organizing your Movie files - Plex Support

You can find matching English subtitles on several dedicated sites: subtitle Unbreakable.2000.1080p.BluRay.x264.DTS...

SubSource – Lists files for various 1080p BrRip and BluRay versions. 2. Prepare for Automatic Loading For your media player to detect the subtitles