Plex is not recognizing all the files in the TV folder on my QNAP NAS

Plex is not recognizing all the files in my TV folder. e.g I have 14 episodes but only 6 show up in Plex all the FAQ’s indicate this is to do with naming but I have made absolutely sure that all files are named as per Plex protocol e.g. TV Shows\Billions\Season01\Billions S01E01.mkv can anyone help

sorry there is a space after Season i.e Season 01