Soo I was doing some testing and I have a /unban command and it unban's an IP aswell but when I try to do so myself, I get this error. Luckily, I can still get on via mobile hotspot with my unlimited data with another account.
Java:
[18:53:14 INFO]: Could not unban player IntelCoreEye7
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! [Skript] Severe Error:
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! If you're developing an add-on for Skript this likely means that you have done something wrong.
[18:53:14 ERROR]: #!#! If you're a server admin however please go to https://github.com/bensku/Skript/issues/
[18:53:14 ERROR]: #!#! and check whether this error has already been reported.
[18:53:14 ERROR]: #!#! If not please create a new ticket with a meaningful title, copy & paste this whole error into it (or use paste service),
[18:53:14 ERROR]: #!#! and describe what you did before it happened and/or what you think caused the error.
[18:53:14 ERROR]: #!#! If you think that it's a trigger that's causing the error please post the trigger as well.
[18:53:14 ERROR]: #!#! By following this guide fixing the error should be easy and done fast.
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! Stack trace:
[18:53:14 ERROR]: #!#! java.lang.NullPointerException
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.GameProfileBanList.b(SourceFile:34)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.GameProfileBanList.a(SourceFile:8)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.JsonList.remove(JsonList.java:90)
[18:53:14 ERROR]: #!#! at org.bukkit.craftbukkit.v1_8_R3.CraftProfileBanList.pardon(CraftProfileBanList.java:97)
[18:53:14 ERROR]: #!#! at ch.njol.skript.effects.EffBan.execute(EffBan.java:134)
[18:53:14 ERROR]: #!#! at ch.njol.skript.lang.Effect.run(Effect.java:54)
[18:53:14 ERROR]: #!#! at ch.njol.skript.lang.TriggerItem.walk(TriggerItem.java:65)
[18:53:14 ERROR]: #!#! at ch.njol.skript.lang.TriggerItem.walk(TriggerItem.java:93)
[18:53:14 ERROR]: #!#! at ch.njol.skript.lang.Trigger.execute(Trigger.java:53)
[18:53:14 ERROR]: #!#! at ch.njol.skript.command.ScriptCommand.execute2(ScriptCommand.java:222)
[18:53:14 ERROR]: #!#! at ch.njol.skript.command.ScriptCommand.execute(ScriptCommand.java:184)
[18:53:14 ERROR]: #!#! at ch.njol.skript.command.Commands.handleCommand(Commands.java:270)
[18:53:14 ERROR]: #!#! at ch.njol.skript.command.Commands$1.onPlayerCommand(Commands.java:165)
[18:53:14 ERROR]: #!#! at sun.reflect.GeneratedMethodAccessor90.invoke(Unknown Source)
[18:53:14 ERROR]: #!#! at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[18:53:14 ERROR]: #!#! at java.lang.reflect.Method.invoke(Method.java:498)
[18:53:14 ERROR]: #!#! at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306)
[18:53:14 ERROR]: #!#! at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
[18:53:14 ERROR]: #!#! at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502)
[18:53:14 ERROR]: #!#! at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1154)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:997)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13)
[18:53:14 ERROR]: #!#! at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[18:53:14 ERROR]: #!#! at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.SystemUtils.a(SourceFile:44)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:715)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654)
[18:53:14 ERROR]: #!#! at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557)
[18:53:14 ERROR]: #!#! at java.lang.Thread.run(Thread.java:748)
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! Version Information:
[18:53:14 ERROR]: #!#! Skript: 2.2-dev23
[18:53:14 ERROR]: #!#! Bukkit: 1.8.8-R0.1-SNAPSHOT
[18:53:14 ERROR]: #!#! Minecraft: 1.8.8
[18:53:14 ERROR]: #!#! Java: 1.8.0_131 (Java HotSpot(TM) 64-Bit Server VM 25.131-b11)
[18:53:14 ERROR]: #!#! OS: Linux amd64 2.6.32-openvz-amd64
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! Running CraftBukkit: false
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! Current node: null
[18:53:14 ERROR]: #!#! Current item: unban the IP address of (the 1st argument >> ch.njol.skript.classes.data.DefaultConverters$2@77df18e2: org.bukkit.OfflinePlayer->org.bukkit.entity.Player)
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! Thread: Server thread
[18:53:14 ERROR]: #!#!
[18:53:14 ERROR]: #!#! End of Error.
[18:53:14 WARN]: #!#!
[18:53:14 WARN]: #!#! [Umbaska] List of plugins:
[18:53:14 WARN]: #!#! WorldEdit - 6.1.7;dd00bb1, ColoredSigns - 0.0.1, AdminFun - 2.5.0, Skript - 2.2-dev23, GroupManager - Pre2.14.1.3 FINAL (Phoenix), BedWars - 1.4.1, skDragon - 0.13.1, SetSpawn - 1.0, SkQuery - 3.21.4, Votifier - 1.9, WorldGuard - 6.2.1;84bc322, SkStuff - 1.6.4.1, Skellett - 1.8.8, iDisguise - 5.5.5, VoxelSniper - 5.171.0-SNAPSHOT, WildSkript - 1.8, skUtilities - 0.5.6, ViaVersion - 1.1.1, GAListener - 1.3.2, Vault - 1.5.6-b49, StaffPlus - 3.2.2, RandomSK - 2.7, CubeRunner - 2.5.2, Commandspy - 4.1.0, EnjinMinecraftPlugin - 3.2.2, PlotSquared - 3.5.0-SNAPSHOT-95f8aaa, ProtocolLib - 4.3.0, Multiverse-Core - 2.5.0-b727, AAC - 3.2.1, Multiverse-Inventories - 2.5.0-SNAPSHOT-b418, Umbaska - 2.0 Beta 5.5.1, HolographicDisplays - 2.2.6, skRayFall - 1.9.7
[18:53:14 WARN]: #!#!
[18:53:14 WARN]: #!#! [Umbaska] List of addons:
[18:53:14 WARN]: #!#! Skellett v1.8.8skDragon v0.13.1skUtilities v0.5.6Umbaska v2.0 Beta 5.5.1skRayFall v1.9.7SkQuery v3.21.4RandomSK v2.7WildSkript v1.8SkStuff v1.6.4.1