Lets make this quick! I was having trouble accessing a mount folder in Plex.
The following worked for me on my Ubuntu Distro.
mkdir -p /home/ghost/peloton sudo mount -B /media/ghost/WD/peloton/ /home/ghost/peloton/
NOTE: I had to mount the EXACT folder using the above mount command!
Use the home folder to add videos! It seems to work perfectly now! FTW!