Plex server could not find the folder with movies

Hello,

this is the first time I use OpenMediaVault. In my NAS I use a SSD (120GB, 2 partitions with ~25GB and ~80GB + an extra partition for swap) and a normal hard disk.

I want to use the second partition with ~80GB for the plex server:

But I can not select the movie folder on my hard disk. It looks like the folder(s) do not exist.

Thanks for your help.