Hello,

the game crashed on loading the config screen with the /cbsconfig (modmenu not showing a config button)
Crash Report: https://pastebin.com/HHf0JtdC
Using mod version: CustomSelectionBox-5.0.0-unstable.jar
MC version: 1.16.1
Fabric Loader version: 0.8.8+build.202-1.16.1

Fixed with v5.0.1 today