[07:03:26] [Server thread/WARN]: handleDisconnection() called twice
[07:03:26] [Server thread/WARN]: [Lobby] Task #16 for Lobby v0.1 generated an exception
java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) ~[?:1.8.0_65]
	at java.util.HashMap$KeyIterator.next(HashMap.java:1453) ~[?:1.8.0_65]
	at org.guildcraft.lobby.Lobby$1.run(Lobby.java:100) ~[?:?]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftTask.run(CraftTask.java:71) ~[spigot.jar:git-Spigot-fdc1440-53fac9f]
	at org.bukkit.craftbukkit.v1_8_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:350) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:722) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:653) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:556) [spigot.jar:git-Spigot-fdc1440-53fac9f]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_65]