Error on tp to nether through nether portal:
[11:00:14] [Server thread/INFO]: Preparing start region for level 8 (Seed: -3228148665334732416)
[11:00:15] [Server thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: net.minecraft.server.v1_8_R2.ReportedException: Ticking player
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_31]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_31]
at net.minecraft.server.v1_8_R2.SystemUtils.a(SourceFile:61) [spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.MinecraftServer.A(MinecraftServer.java:712) [spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.DedicatedServer.A(DedicatedServer.java:368) [spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.MinecraftServer.z(MinecraftServer.java:651) [spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.MinecraftServer.run(MinecraftServer.java:554) [spigot.jar:git-Spigot-870264a-0a645a2]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_31]
Caused by: net.minecraft.server.v1_8_R2.ReportedException: Ticking player
at net.minecraft.server.v1_8_R2.EntityPlayer.l(EntityPlayer.java:350) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PlayerConnection.a(PlayerConnection.java:382) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PacketPlayInFlying.a(SourceFile:126) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PacketPlayInFlying$PacketPlayInPosition.a(SourceFile:57) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PlayerConnectionUtils$1.run(SourceFile:13) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_31]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_31]
at net.minecraft.server.v1_8_R2.SystemUtils.a(SourceFile:60) ~[spigot.jar:git-Spigot-870264a-0a645a2]
... 5 more
Caused by: java.lang.NullPointerException
at org.bukkit.craftbukkit.v1_8_R2.CraftTravelAgent.findOrCreate(CraftTravelAgent.java:27) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PlayerList.changeDimension(PlayerList.java:671) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.EntityPlayer.c(EntityPlayer.java:536) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.Entity.K(Entity.java:279) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.EntityLiving.K(EntityLiving.java:169) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.Entity.t_(Entity.java:246) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.EntityLiving.t_(EntityLiving.java:1447) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.EntityHuman.t_(EntityHuman.java:173) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.EntityPlayer.l(EntityPlayer.java:285) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PlayerConnection.a(PlayerConnection.java:382) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PacketPlayInFlying.a(SourceFile:126) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PacketPlayInFlying$PacketPlayInPosition.a(SourceFile:57) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at net.minecraft.server.v1_8_R2.PlayerConnectionUtils$1.run(SourceFile:13) ~[spigot.jar:git-Spigot-870264a-0a645a2]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_31]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_31]
at net.minecraft.server.v1_8_R2.SystemUtils.a(SourceFile:60) ~[spigot.jar:git-Spigot-870264a-0a645a2]
... 5 more