You ran out of biome IDS. Remove some mods that adds biomes.
NotEnoughIDs is a coremod that extends hardcoded ID limit for blocks and items.
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Say something silly, Laugh 'til it hurts, Take a risk, Sing out loud, Rock the boat, Shake things up, Flirt with disaster, Buy something frivolous, Color outside the lines, Cause a scene, Order dessert, Make waves, Get carried away, Have a great day!