Hey i put a modpack together and the server runs but nobody can join the server because you get 
 
	Internal Exception: io.netty.handler.codec.DecoderException: java.lang.NullPointerException: Cannot invoke "net.minecraft.resources.ResourceLocation.toString()" because "book" is null 
 
	i searched for the error but couldnd find anything 
	 
	Client log: https://mclo.gs/0ha2gTa 
	Server Log: https://mclo.gs/wdpqnH3