[04:05:11] [Netty Epoll Server IO #1/ERROR]: java.lang.NullPointerException: Cannot invoke "net.minecraft.server.v1_16_R3.ChatMessageType.a()" because "this.b" is null [04:05:11] [Netty Epoll Server IO #1/WARN]: java.lang.NullPointerException: Cannot invoke "net.minecraft.server.v1_16_R3.ChatMessageType.a()" because "this.b" is null [04:05:11] [Netty Epoll Server IO #1/WARN]: at net.minecraft.server.v1_16_R3.PacketPlayOutChat.b(PacketPlayOutChat.java:44) [04:05:11] [Netty Epoll Server IO #1/WARN]: at net.minecraft.server.v1_16_R3.PacketEncoder.encode(PacketEncoder.java:42) [04:05:11] [Netty Epoll Server IO #1/WARN]: at net.minecraft.server.v1_16_R3.PacketEncoder.encode(PacketEncoder.java:12) [04:05:11] [Netty Epoll Server IO #1/WARN]: at jdk.internal.reflect.GeneratedMethodAccessor60.invoke(Unknown Source) [04:05:11] [Netty Epoll Server IO #1/WARN]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [04:05:11] [Netty Epoll Server IO #1/WARN]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [04:05:11] [Netty Epoll Server IO #1/WARN]: at us.myles.ViaVersion.util.PipelineUtil.callEncode(PipelineUtil.java:71) [04:05:11] [Netty Epoll Server IO #1/WARN]: at us.myles.ViaVersion.bukkit.handlers.BukkitEncodeHandler.encode(BukkitEncodeHandler.java:49) [04:05:11] [Netty Epoll Server IO #1/WARN]: at jdk.internal.reflect.GeneratedMethodAccessor59.invoke(Unknown Source) [04:05:11] [Netty Epoll Server IO #1/WARN]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [04:05:11] [Netty Epoll Server IO #1/WARN]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelInjector.encode(ChannelInjector.java:525) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelInjector.access$100(ChannelInjector.java:67) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelInjector$1.encode(ChannelInjector.java:265) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.handler.codec.MessageToByteEncoder.write(MessageToByteEncoder.java:107) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelInjector$1.write(ChannelInjector.java:271) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:709) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:792) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:702) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.ChannelDuplexHandler.write(ChannelDuplexHandler.java:115) [04:05:11] [Netty Epoll Server IO #1/WARN]: at me.neznamy.tab.platforms.bukkit.BukkitPipelineInjector$1.write(BukkitPipelineInjector.java:76) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:709) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:792) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:702) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.ChannelDuplexHandler.write(ChannelDuplexHandler.java:115) [04:05:11] [Netty Epoll Server IO #1/WARN]: at su.nexmedia.engine.nms.packets.PacketManager$1.write(PacketManager.java:109) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:709) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:792) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:702) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:110) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:764) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:808) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1025) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:294) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelProxy.writeAndFlush(ChannelProxy.java:327) [04:05:11] [Netty Epoll Server IO #1/WARN]: at net.minecraft.server.v1_16_R3.NetworkManager$1.run(NetworkManager.java:409) [04:05:11] [Netty Epoll Server IO #1/WARN]: at com.comphenix.protocol.injector.netty.ChannelInjector$3.lambda$onMessageScheduled$1(ChannelInjector.java:348) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:387) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) [04:05:11] [Netty Epoll Server IO #1/WARN]: at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [04:05:11] [Netty Epoll Server IO #1/WARN]: at java.base/java.lang.Thread.run(Thread.java:832)

Server version 1.16.4
Java 15.0.1
Protocollib the latest build 486

Here is the protocol dump:
https://pastebin.com/C9bdpYyZ