Minecraft: 1.17.1
Health Overlay: 3.0.2
Forge: 37.0.22
Optifine Installed?: No (Not compatible with forge 1.17 yet)
Crash Report: https://pastebin.com/XKmMWihH
Log: latest.log

Found the issue
[06:50:35] [modloading-worker-1/ERROR]: Absorption effect colors must either be empty or have 2 values.
One of your absorption effect colours are probably empty and the code is currently only working with 2 values. I'm unfortunately not able to fix it currently so for now you can just give it 2 colours. There are defaults but it may require deleting the config file.