undertrox

Hello, I'm trying to make an addon for another mod, which obviously requires me to test it with that mod loaded, but when I put any mod into the run/mods folder, Minecraft will start with an error message, saying "the mod encountered an error during the load_registries phase" (depending on the mod, it is sometimes a different phase). The log usually shows either a NoSuchFieldError or a NoSuchMethodError, again, depending on what mod I try to load. I even tried using deobfuscated jars of mods that have them, but then I just get a different NoSuchFieldError. The file I uploaded is the log for when I tried to load Biomes o Plenty, though I doubt it will help. Does anyone know what I need to do differently? latest.log