GatherDataEvent not firing when runData

@Mod.EventBusSubscriber(modid = BetterLeveling.MOD_ID, bus = Mod.EventBusSubscriber.Bus.MOD)
public class ModEvents {
    @SubscribeEvent
    public void gatherData(GatherDataEvent event) {
        DataGenerator generator = event.getGenerator();
        PackOutput packOutput = generator.getPackOutput();
        ExistingFileHelper existingFileHelper = event.getExistingFileHelper();
        CompletableFuture<HolderLookup.Provider> lookupProvider = event.getLookupProvider();

        ModBlockTagsProvider blockTagsProvider = new ModBlockTagsProvider(packOutput, lookupProvider, existingFileHelper);

        generator.addProvider(event.includeServer(), blockTagsProvider);
        generator.addProvider(event.includeServer(), new ModItemTagsProvider(packOutput, lookupProvider, blockTagsProvider, existingFileHelper));
        generator.addProvider(event.includeClient(), new ModLanguageProvider(packOutput, "en_us"));
    }
}