Minecraft 1.9.2 Server Issue!!

So i got this code in the console every minute plz help
It's a Spigot 1.9.2 Server hosted with Server.pro
I don't know if it's a plugin exception or the spigot exception if you know how to fix it plz reply the solution ASAP

[05:06:40 WARN]: java.lang.Throwable: Unexpected NavigationListener add
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.NavigationListener.a(NavigationListener.java:16)
[05:06:40 WARN]: at net.citizensnpcs.util.nms.PlayerNavigation.<init>(PlayerNavigation.java:51)
[05:06:40 WARN]: at net.citizensnpcs.npc.entity.EntityHumanNPC.initialise(EntityHumanNPC.java:261)
[05:06:40 WARN]: at net.citizensnpcs.npc.entity.EntityHumanNPC.<init>(EntityHumanNPC.java:84)
[05:06:40 WARN]: at net.citizensnpcs.npc.entity.HumanController.createEntity(HumanController.java:82)
[05:06:40 WARN]: at net.citizensnpcs.npc.AbstractEntityController.spawn(AbstractEntityController.java:35)
[05:06:40 WARN]: at net.citizensnpcs.npc.CitizensNPC.spawn(CitizensNPC.java:192)
[05:06:40 WARN]: at net.citizensnpcs.EventListen.spawn(EventListen.java:497)
[05:06:40 WARN]: at net.citizensnpcs.EventListen.respawnAllFromCoord(EventListen.java:474)
[05:06:40 WARN]: at net.citizensnpcs.EventListen.onChunkLoad(EventListen.java:129)
[05:06:40 WARN]: at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
[05:06:40 WARN]: at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[05:06:40 WARN]: at java.lang.reflect.Method.invoke(Method.java:498)
[05:06:40 WARN]: at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306)
[05:06:40 WARN]: at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
[05:06:40 WARN]: at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502)
[05:06:40 WARN]: at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:55)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:1)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.util.AsynchronousExecutor.skipQueue(AsynchronousExecutor.java:337)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.util.AsynchronousExecutor.getSkipQueue(AsynchronousExecutor.java:295)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.chunkio.ChunkIOExecutor.syncChunkLoad(ChunkIOExecutor.java:16)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:136)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:118)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.ChunkProviderServer.getOrCreateChunkFast(ChunkProviderServer.java:76)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.CraftWorld.getChunkAt(CraftWorld.java:128)
[05:06:40 WARN]: at org.bukkit.craftbukkit.v1_9_R1.CraftWorld.getChunkAt(CraftWorld.java:617)
[05:06:40 WARN]: at org.bukkit.Location.getChunk(Location.java:78)
[05:06:40 WARN]: at com.sainttx.holograms.HologramListener.lambda$onChunkUnload$4(HologramListener.java:43)
[05:06:40 WARN]: at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
[05:06:40 WARN]: at java.util.TreeMap$ValueSpliterator.forEachRemaining(TreeMap.java:2893)
[05:06:40 WARN]: at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
[05:06:40 WARN]: at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
[05:06:40 WARN]: at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
[05:06:40 WARN]: at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
[05:06:40 WARN]: at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
[05:06:40 WARN]: at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
[05:06:40 WARN]: at com.sainttx.holograms.HologramListener.onChunkUnload(HologramListener.java:44)
[05:06:40 WARN]: at sun.reflect.GeneratedMethodAccessor58.invoke(Unknown Source)
[05:06:40 WARN]: at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[05:06:40 WARN]: at java.lang.reflect.Method.invoke(Method.java:498)
[05:06:40 WARN]: at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306)
[05:06:40 WARN]: at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
[05:06:40 WARN]: at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502)
[05:06:40 WARN]: at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:289)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.WorldServer.doTick(WorldServer.java:233)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.MinecraftServer.D(MinecraftServer.java:776)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.DedicatedServer.D(DedicatedServer.java:400)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.MinecraftServer.C(MinecraftServer.java:660)
[05:06:40 WARN]: at net.minecraft.server.v1_9_R1.MinecraftServer.run(MinecraftServer.java:559)
[05:06:40 WARN]: at java.lang.Thread.run(Thread.java:745)