cerror

X_Cosmic_X issued server command: /c
X_Cosmic_X has completed the Helldorado challenge!
Could not pass event InventoryClickEvent to uSkyBlock v2.7.2
org.bukkit.event.EventException
	at org.bukkit.plugin.EventExecutor$1.execute(EventExecutor.java:46) ~[patched_1.10.2.jar:git-Paper-819]
	at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:78) ~[patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:517) [patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:502) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.PlayerConnection.a(PlayerConnection.java:1902) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.PacketPlayInWindowClick.a(SourceFile:33) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.PacketPlayInWindowClick.a(SourceFile:10) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.PlayerConnectionUtils$1.run(SourceFile:13) [patched_1.10.2.jar:git-Paper-819]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_77]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_77]
	at net.minecraft.server.v1_10_R1.SystemUtils.a(SourceFile:45) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:791) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:404) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:725) [patched_1.10.2.jar:git-Paper-819]
	at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:624) [patched_1.10.2.jar:git-Paper-819]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_77]
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:47) ~[patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:152) ~[patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:665) ~[patched_1.10.2.jar:git-Paper-819]
	at org.bukkit.craftbukkit.v1_10_R1.entity.CraftPlayer.performCommand(CraftPlayer.java:336) ~[patched_1.10.2.jar:git-Paper-819]
	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 com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor2366.execute(Unknown Source) ~[?:?]
	at org.bukkit.plugin.EventExecutor$1.execute(EventExecutor.java:44) ~[patched_1.10.2.jar:git-Paper-819]
	... 16 more
Caused by: java.lang.NullPointerException