[17:00:14 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'questadmin' in plugin Quests v3.6.8-b747
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:48) ~[patched_1.13.2.jar:git-Paper-626]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:151) ~[patched_1.13.2.jar:git-Paper-626]
	at org.bukkit.craftbukkit.v1_13_R2.CraftServer.dispatchCommand(CraftServer.java:734) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.PlayerConnection.handleCommand(PlayerConnection.java:1783) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.PlayerConnection.a(PlayerConnection.java:1591) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.PacketPlayInChat.a(PacketPlayInChat.java:45) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:15) ~[patched_1.13.2.jar:git-Paper-626]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_201]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_201]
	at net.minecraft.server.v1_13_R2.SystemUtils.a(SystemUtils.java:108) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.MinecraftServer.b(MinecraftServer.java:1018) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.DedicatedServer.b(DedicatedServer.java:439) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.MinecraftServer.a(MinecraftServer.java:940) ~[patched_1.13.2.jar:git-Paper-626]
	at net.minecraft.server.v1_13_R2.MinecraftServer.run(MinecraftServer.java:837) ~[patched_1.13.2.jar:git-Paper-626]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_201]
Caused by: java.util.ConcurrentModificationException
	at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:966) ~[?:1.8.0_201]
	at java.util.LinkedList$ListItr.next(LinkedList.java:888) ~[?:1.8.0_201]
	at me.blackvein.quests.listeners.CmdExecutor.adminReset(CmdExecutor.java:1338) ~[?:?]
	at me.blackvein.quests.listeners.CmdExecutor.questAdminCommandHandler(CmdExecutor.java:270) ~[?:?]
	at me.blackvein.quests.listeners.CmdExecutor.onCommand(CmdExecutor.java:85) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[patched_1.13.2.jar:git-Paper-626]
	... 15 more