Plex Documentation → Your Media → Naming & Organizing Your TV Show Files
This usually comes down to file/folder permissions or naming & organization.
You don’t mention PMS version, platform, etc. So, if the files are stored on a NAS, external drive, etc., make sure Plex has at least read-only permissions to the folders and files.
Make sure you follow Plex naming and organization requirements. If you make any changes, you will need to Plex Dance the show. The process removes bad matching information from the Plex database.
If Plex still is not recognizing the media, please post a directory listing, screenshot, etc of how you have the files named and organized. Please mention which folder is added to the TV show library and also include the file extension for the files (mkv, m4v, etc).
