Server thread dump, need help

I get this error on my servers console and don’t really know what to do:

31.05 13:30:33 [Server] ERROR ------------------------------
31.05 13:30:33 [Server] ERROR — DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH —
31.05 13:30:33 [Server] ERROR ------------------------------
31.05 13:30:39 [Server] ERROR — DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH - git-Paper-304 (MC: 1.15.2) —
31.05 13:30:39 [Server] ERROR The server has not responded for 16 seconds! Creating thread dump
31.05 13:30:39 [Server] ERROR ------------------------------
31.05 13:30:39 [Server] ERROR Server thread dump (Look for plugins here before reporting to Paper!):
31.05 13:30:41 [Server] ERROR ------------------------------
31.05 13:30:41 [Server] ERROR Current Thread: Server thread
31.05 13:30:41 [Server] ERROR PID: 25 | Suspended: false | Native: false | State: RUNNABLE
31.05 13:30:41 [Server] ERROR Stack:
31.05 13:30:41 [Server] ERROR java.util.Arrays.copyOf(Arrays.java:3181)
31.05 13:30:41 [Server] ERROR java.util.ArrayList.grow(ArrayList.java:265)
31.05 13:30:41 [Server] ERROR java.util.ArrayList.ensureExplicitCapacity(ArrayList.java:239)
31.05 13:30:41 [Server] ERROR java.util.ArrayList.ensureCapacityInternal(ArrayList.java:231)
31.05 13:30:41 [Server] ERROR java.util.ArrayList.add(ArrayList.java:479)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.NBTTagList.b(NBTTagList.java:265)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.NBTTagList.add(NBTTagList.java:247)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.NBTTagList.add(NBTTagList.java:16)
31.05 13:30:41 [Server] ERROR java.util.AbstractList.add(AbstractList.java:108)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard.a(SourceFile:352)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard$$Lambda$4568/1996677138.accept(Unknown Source)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
31.05 13:30:41 [Server] ERROR java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175)
31.05 13:30:41 [Server] ERROR java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1628)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
31.05 13:30:41 [Server] ERROR java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard.a(SourceFile:346)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard$$Lambda$4566/808823073.accept(Unknown Source)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
31.05 13:30:41 [Server] ERROR java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
31.05 13:30:41 [Server] ERROR java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1628)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
31.05 13:30:41 [Server] ERROR java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
31.05 13:30:41 [Server] ERROR java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
31.05 13:30:41 [Server] ERROR java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard.i(SourceFile:345)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.PersistentScoreboard.b(PersistentScoreboard.java:163)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.PersistentBase.a(SourceFile:48)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.WorldPersistentData.a(WorldPersistentData.java:171)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.WorldServer.m_(WorldServer.java:1055)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.WorldServer.save(WorldServer.java:1030)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.MinecraftServer.saveChunks(MinecraftServer.java:691)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.CommandSaveAll.a(SourceFile:34)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.CommandSaveAll.b(SourceFile:20)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.CommandSaveAll$$Lambda$1878/2054758027.run(Unknown Source)
31.05 13:30:41 [Server] ERROR com.mojang.brigadier.CommandDispatcher.execute(CommandDispatcher.java:262)
31.05 13:30:41 [Server] ERROR com.mojang.brigadier.CommandDispatcher.execute(CommandDispatcher.java:176)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.CommandDispatcher.a(CommandDispatcher.java:179)
31.05 13:30:41 [Server] ERROR org.bukkit.craftbukkit.v1_15_R1.command.VanillaCommandWrapper.execute(VanillaCommandWrapper.java:45)
31.05 13:30:41 [Server] ERROR org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159)
31.05 13:30:41 [Server] ERROR org.bukkit.craftbukkit.v1_15_R1.CraftServer.dispatchCommand(CraftServer.java:761)
31.05 13:30:41 [Server] ERROR org.bukkit.craftbukkit.v1_15_R1.CraftServer.dispatchServerCommand(CraftServer.java:723)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.DedicatedServer.handleCommandQueue(DedicatedServer.java:469)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:431)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:1173)
31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:962)
31.05 13:30:41 [Server] ERROR java.lang.Thread.run(Thread.java:748)
31.05 13:30:41 [Server] ERROR ------------------------------
31.05 13:30:41 [Server] ERROR — DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH —
31.05 13:30:41 [Server] ERROR ------------------------------

It is a plugin that is causing this problem, I think it has to do with this:

31.05 13:30:41 [Server] ERROR net.minecraft.server.v1_15_R1.Scoreboard.i(SourceFile:345)
31.05 13:30:41 [Server] ERROR