[14:20:09 INFO]: [ShopGUIPlus] Enabling ShopGUIPlus v1.19.1
[14:20:09 INFO]: [ShopGUIPlus] Permissions support enabled.
[14:20:09 INFO]: [ShopGUIPlus] EpicSpawners support enabled.
[14:20:09 ERROR]: Error occurred while enabling ShopGUIPlus v1.19.1 (Is it up to date?)
java.lang.IllegalArgumentException: Material cannot be null
        at org.apache.commons.lang.Validate.notNull(Validate.java:192) ~[Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.inventory.ItemStack.<init>(ItemStack.java:69) ~[Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.inventory.ItemStack.<init>(ItemStack.java:57) ~[Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.brcdev.shopgui.util.ItemUtils.loadItemStackFromConfig(ItemUtils.java:125) ~[?:?]
        at net.brcdev.shopgui.settings.MenuSettings.load(MenuSettings.java:71) ~[?:?]
        at net.brcdev.shopgui.settings.MenuSettings.<init>(MenuSettings.java:22) ~[?:?]
        at net.brcdev.shopgui.settings.MenuWithItemSettings.<init>(MenuWithItemSettings.java:14) ~[?:?]
        at net.brcdev.shopgui.config.Settings.load(Settings.java:368) ~[?:?]
        at net.brcdev.shopgui.config.Settings.setConfig(Settings.java:147) ~[?:?]
        at net.brcdev.shopgui.ShopGuiPlugin.load(ShopGuiPlugin.java:188) ~[?:?]
        at net.brcdev.shopgui.ShopGuiPlugin.onEnable(ShopGuiPlugin.java:146) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:254) ~[Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:339) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:403) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.craftbukkit.v1_13_R2.CraftServer.enablePlugin(CraftServer.java:431) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at org.bukkit.craftbukkit.v1_13_R2.CraftServer.enablePlugins(CraftServer.java:345) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.minecraft.server.v1_13_R2.MinecraftServer.l(MinecraftServer.java:584) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:546) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:424) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.minecraft.server.v1_13_R2.DedicatedServer.init(DedicatedServer.java:294) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:702) [Simplex.jar:git-Spigot-2474d93-ca22de3]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_192]