The game crashed whilst unexpected error Error: java.lang.NullPointerException: Cannot invoke "net.minecraftforge.common.ForgeConfigSpec$BooleanValue.get()" because "net.ludocrypt.musicdr.config.MusicConfig.divide" is null
What I've gathered from this crash is the game is reading the config file wrong, as it says the value for "divide" is null, despite the fact it has the default number in it as I haven't changed it.

I am getting this too, but for me, it seems to be something when I install a mod that needs a different forge version.

Instead of getting the error screen from that mod, stating that I need a forge update, it just crashes with the null report.

I Also got that. Needs Urgent Fix.

I can also state that this issue is indeed occurring on the Forge version. Specifically Forge version 39.0.64