Cheers!

A user came to me with a crash log that points back to your mod's config registration not being called. Specific error is from AutoConfig, stating specifically that Config 'class io.github.madis0.ModConfig' has not been registered.

Crash log can be found here:
crash-2021-03-17_14.01.09-client-1.txt

Thanks for letting me know! Pretty sure I know the cause and will push an update soon.
Edit: 1.2.1 is uploaded in CurseForge and others, you can tell the user.