I've been trying to do a survival world for this mod, but for some reason mobs are refusing to spawn naturally. These are new worlds that have not been played on before, nor do i have any other biome mods or anything of the sort.

The only mobs i have seen are the newer mobs that were recently added. but anything before that just basically doesn't spawn naturally.

Does anyone know how to fix this issue? i would greatly appreciate it.

delete the config

then reopen forge it worked for me :)