[16:31:05 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'player' in plugin NexusPrefix v1.1.1
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at org.bukkit.craftbukkit.v1_12_R1.CraftServer.dispatchCommand(CraftServer.java:645) ~[forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.PlayerConnection.handleCommand(PlayerConnection.java:1385) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.PlayerConnection.a(PlayerConnection.java:1220) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.PlayerConnectionUtils$1.run(SourceFile:13) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_101]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_101]
	at net.minecraft.server.v1_12_R1.SystemUtils.a(SourceFile:46) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:747) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:405) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:678) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:576) [forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_101]
Caused by: java.lang.NullPointerException
	at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:770) ~[forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	at ru.den_abr.nexusprefix.NexusPrefixPlugin.activate(NexusPrefixPlugin.java:115) ~[?:?]
	at ru.den_abr.nexusprefix.NexusPrefixPlugin.onCommand(NexusPrefixPlugin.java:85) ~[?:?]
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[forscraft.jar:git-Spigot-99c2a37-c1b8cac]
	... 15 more