I'm using version : Waystones_1.16.1-7.0.2.jar
In singleplayer the gui button ( the scroll) is there and working perfectly.
In a multiplayer world (server), there is no button.
The server config on the server is set to 'NEAREST' . I used the same config on both singleplayer and server.

Where did you place the config file on the server? Waystones 1.16+ is looking for it in the normal config folder again, no longer inside the world folder.

Yes just in the normal config folder