[02:16:48] [Server thread/ERROR]: Error occurred while enabling DropEdit2 v1.1.23-SNAPSHOT (Is it up to date?)
java.lang.IllegalArgumentException: Material cannot be null
	at org.apache.commons.lang.Validate.notNull(Validate.java:192) ~[craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.inventory.ItemStack.<init>(ItemStack.java:70) ~[craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.inventory.ItemStack.<init>(ItemStack.java:58) ~[craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at de.Linus122.GUI.Utils.createStack(Utils.java:28) ~[?:?]
	at de.Linus122.GUI.Guis.GUIHandler.init(GUIHandler.java:26) ~[?:?]
	at de.Linus122.DropEdit.Main.onEnable(Main.java:98) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:263) ~[craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:352) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:417) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.craftbukkit.v1_15_R1.CraftServer.enablePlugin(CraftServer.java:462) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at org.bukkit.craftbukkit.v1_15_R1.CraftServer.enablePlugins(CraftServer.java:376) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:456) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at net.minecraft.server.v1_15_R1.DedicatedServer.init(DedicatedServer.java:266) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:783) [craftbukkit.jar:git-Spigot-530f668-de42aa1]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_171]