error 2

[19:01:27] [User Authenticator #10/INFO]: UUID of player MC_Rainy is 8cb4a167-4b17-48c6-bf17-97d18218da1e
[19:01:27] [Server thread/INFO]: [YourMC] Loaded data for player 'MC_Rainy'.
[19:01:27] [Server thread/INFO]: MC_Rainy[/68.150.168.244:49220] logged in with entity id 69602 at ([world]2213.1046838498837, 74.0, 1069.3790406955109)
[19:01:27] [Server thread/WARN]: [Essentials] Task #6893 for Essentials vTeamCity generated an exception
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) ~[?:1.8.0_45]
	at java.util.HashMap$KeyIterator.next(HashMap.java:1453) ~[?:1.8.0_45]
	at net.minecraft.server.v1_8_R3.EntityTracker.a(EntityTracker.java:202) ~[spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.EntityPlayer.B(EntityPlayer.java:1038) ~[spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.EntityPlayer.updateAbilities(EntityPlayer.java:934) ~[spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at org.bukkit.craftbukkit.v1_8_R3.entity.CraftPlayer.setFlySpeed(CraftPlayer.java:1186) ~[spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at com.earth2me.essentials.EssentialsPlayerListener$1DelayJoinTask.run(EssentialsPlayerListener.java:350) ~[?:?]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:726) [spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) [spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) [spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot.jar:git-Spigot-6a6b839-b0e81a4]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]
[19:01:29] [Server thread/INFO]: Member horseylover52402: wb
[19:01:30] [Server thread/INFO]: Member BCPlaysMC: wb
[19:01:32] [Server thread/INFO]: Member Ben10142002: wb