chatcommand return true, because false display in chat "invalid command usage", but there is already a message, it's ambigus(i retry some time and check code to anderstand why it fail :p ).

guide.lua

@@ -373,11 +373,11 @@ minetest.register_chatcommand("hell_help", {
 		local player = minetest.get_player_by_name(name)
 		if not player then
 			minetest.chat_send_player(name, "Something went wrong.")
-			return false
+			return true
 		end
 		if player:get_pos().y > hell.start then
 			minetest.chat_send_player(name, S("Usually you don't need this guide here. You can view it in the hell."))
-			return false
+			return true
 		end
 		minetest.chat_send_player(name, S("Showing guide..."))
 		show_guide(name)