"Added By Default" Breaks the plugin

I bought this plugin for one simple solution. I just want to allow players to be able to use the Waystone at a location that I build on the ground in order to teleport to a lobby area I have build for an arena in the sky. I am not interested in allowing players to build the Waystones so I do n ot want them to be required to "Assign" on the Waystones. 

When I change the "Added By Default" function in the config, the plugin breaks and gives the below error in the console.

answered on discord