Thanks Sal_Khan!
Plex really needs to add something to their software explaining this. “Your changes could not be saved.” is an example of worthless and lazy programming. Time killing, sloppy mistake that costs all users needless time.
Luckily, Sal_Kahn has saved me a bunch of time and frustration by patiently figuring this out for all of the Plex staff that must have had better things to do than test their stuff.