So I ran into this issue with a client where Network Discovery turns off after I try to turn it on and click Save.
I then went and checked on the setting and it was sent back to off. It did not make sense what was going on.
I did some google searching and found this on the Microsoft Forum
I could end this post here, but just encase the post gets deleted, here is a list of the services that you need to make sure are Enabled and Running to turn on Network Discovery.