about SpawnPacket extends EntitySpawnS2CPacket

[wupengyang1995]

Hi, brother,
I'm in trouble, I have a spawnPacket alse extends EntitySpawnS2CPacket like you do,
it run ok in singleplayer, but i put the mod on fabric server it crash:

Description: Exception in server tick loop

java.lang.NoClassDefFoundError: net/minecraft/class_638
	at net.metacraft.mod.painting.MetaPaintingEntity.method_18002(MetaPaintingEntity.java:202)

I don't know why clientworld(class_638) appear on server?

I think this mod put one on client and other put one on server? ,Did I get it wrong?

below is my code

I hope I can get your help，thanks