Plex is running as a service on your Linux, using its own user (plex).
If you’re mounting the NAS with your own account, it won’t be available to the plex user by default. Also… it’s not enough to bookmark it… you’ll need to mount the NAS drive/share in your local file system.
There’s a post in the Linux tips & tricks section on how to mount a NAS drive so your server can actually access its content (depending on the technology used to share the NAS drives):
PS:
you might find some other useful tips & tricks in that thread
