[20:47:00 ERROR]: Could not pass event PlayerToggleFlightEvent to DoubleJump v13.0
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:1896) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.PacketPlayInAbilities.a(SourceFile:70) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.PacketPlayInAbilities.a(SourceFile:9) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_112]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_112]
        at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:715) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_112]
Caused by: java.lang.IllegalArgumentException: No enum constant org.bukkit.Sound.ENTITY_SLIME_JUMP
        at java.lang.Enum.valueOf(Enum.java:238) ~[?:1.8.0_112]
        at org.bukkit.Sound.valueOf(Sound.java:1) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]
        at me.newkad.doublej.DoubleJump.onFly(DoubleJump.java:180) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor193.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_112]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_112]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-1.8.8.jar:git-Spigot-21fe707-e1ebe52]