[16:17:03 ERROR]: Could not pass event InventoryClickEvent to uSkyBlock v2.7.2
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.java:1854) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.PacketPlayInWindowClick.a(SourceFile:33) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.PacketPlayInWindowClick.a(SourceFile:10) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_74]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_74]
        at net.minecraft.server.v1_10_R1.SystemUtils.a(SourceFile:45) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:732) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:400) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:668) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:567) [spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_74]
Caused by: org.bukkit.command.CommandException: Unhandled exception executing command 'c' in plugin uSkyBlock v2.7.2
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:140) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:646) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at org.bukkit.craftbukkit.v1_10_R1.entity.CraftPlayer.performCommand(CraftPlayer.java:243) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        at us.talabrek.ultimateskyblock.menu.SkyBlockMenu.onClickChallengeMenu(SkyBlockMenu.java:958) ~[?:?]
        at us.talabrek.ultimateskyblock.menu.SkyBlockMenu.onClick(SkyBlockMenu.java:697) ~[?:?]
        at us.talabrek.ultimateskyblock.event.MenuEvents.guiClick(MenuEvents.java:28) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor665.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_74]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_74]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-1.10.2_31.07.jar:git-Spigot-90f61bc-83a9dbd]
        ... 15 more
Caused by: java.lang.NullPointerException