i have just put a 8 gig movie file on my hard drive but plex will not find it when i scan the files

Plex Media Server NAS & Devices
1

i have just added a 8gig movie to my hard drive but plex will not find it when i do a scan on the movies file it is the largest file i have most of the other s are less than 4 gig

2

What is the file extension…avi, mkv, other?