Stack Trace:
java.lang.IllegalArgumentException: Unable to find a field null with the type com.mojang.authlib.GameProfile in net.minecraft.network.protocol.login.PacketLoginInStart
at ProtocolLib.jar//com.comphenix.protocol.reflect.FuzzyReflection.getFieldByType(FuzzyReflection.java:397)
at ProtocolLib.jar//com.comphenix.protocol.reflect.accessors.Accessors.getFieldAccessor(Accessors.java:57)
at ProtocolLib.jar//com.comphenix.protocol.injector.netty.ChannelInjector.handleLogin(ChannelInjector.java:658)
at ProtocolLib.jar//com.comphenix.protocol.injector.netty.ChannelInjector.decode(ChannelInjector.java:591)
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:519)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:458)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:280)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:336)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:308)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at ProtocolLib.jar//com.comphenix.protocol.injector.netty.ChannelInjector$2.channelRead(ChannelInjector.java:292)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:336)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:308)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.handler.flush.FlushConsolidationHandler.channelRead(FlushConsolidationHandler.java:152)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:800)
at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:499)
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:397)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.base/java.lang.Thread.run(Thread.java:833)
Dump:
Parameters:
io.netty.buffer.PooledUnsafeDirectByteBuf@4e00dfa4[
memoryAddress=139915606462640
recyclerHandle=io.netty.util.Recycler$DefaultHandle@3c27a26d
chunk=Chunk(391cbf81: 19%, 778240/4194304)
handle=17451512980570113
memory=java.nio.DirectByteBuffer[pos=0 lim=4194304 cap=4194304]
offset=254000
length=34
maxLength=48
cache=io.netty.buffer.PoolThreadCache@1b176987
tmpNioBuf=
allocator=PooledByteBufAllocator(directByDefault: true)
refCnt=2
readerIndex=34
writerIndex=34
markedReaderIndex=0
markedWriterIndex=0
maxCapacity=2147483647
]
manager:
com.comphenix.protocol.injector.PacketFilterManager@25175689[
unhookTask=com.comphenix.protocol.injector.DelayedSingleTask@4f6f071e
packetListeners=[]
packetInjector=com.comphenix.protocol.injector.netty.ProtocolInjector$5@1661297d
playerInjection=com.comphenix.protocol.injector.netty.ProtocolInjector$4@710d7c1f
inputBufferedPackets=[]
recievedListeners=com.comphenix.protocol.injector.SortedPacketListenerList@6eb1dfa9
sendingListeners=com.comphenix.protocol.injector.SortedPacketListenerList@59516296
hasClosed=false
classLoader=PluginClassLoader{plugin=ProtocolLib v4.8.0, pluginEnabled=true, url=plugins/ProtocolLib.jar}
reporter=com.comphenix.protocol.ProtocolLib$1@5c93f347
server=CraftServer{serverName=Paper,serverVersion=git-Paper-372,minecraftVersion=1.19.3}
library=ProtocolLib v4.8.0
asyncFilterManager=com.comphenix.protocol.async.AsyncFilterManager@6e28b338
knowsServerPackets=true
knowsClientPackets=true
phaseLoginCount=0
phasePlayingCount=0
packetCreation=false
nettyInjector=com.comphenix.protocol.injector.netty.ProtocolInjector@218b1a03
pluginVerifier=com.comphenix.protocol.injector.PluginVerifier@5b8cd36d
hasRecycleDistance=true
minecraftVersion=(MC: 1.19.3)
debug=false
]
Sender:
com.comphenix.protocol.injector.netty.ChannelInjector@125b664b[
decodeBuffer=protected void net.minecraft.network.PacketDecoder.decode(io.netty.channel.ChannelHandlerContext,io.netty.buffer.ByteBuf,java.util.List) throws java.lang.Exception
encodeBuffer=protected void net.minecraft.network.PacketEncoder.encode(io.netty.channel.ChannelHandlerContext,java.lang.Object,io.netty.buffer.ByteBuf) throws java.lang.Exception
factory=com.comphenix.protocol.injector.netty.InjectionFactory@7499f0ba
player=CraftPlayer{name=Joni6227}
updated=
playerName=Joni6227
playerConnection=
networkManager=net.minecraft.network.NetworkManager@7f3d028e
originalChannel=[id: 0x34901cb5, L:/172.18.0.57:20042 - R:/89.246.53.144:19462]
channelField=VolatileField [accessor=DefaultFieldAccessor [field=public io.netty.channel.Channel net.minecraft.network.NetworkManager.m], container=net.minecraft.network.NetworkManager@7f3d028e, previous=[id: 0x34901cb5, L:/172.18.0.57:20042 - R:/89.246.53.144:19462], current=com.comphenix.protocol.injector.netty.ChannelInjector$3@75c38d53, previousLoaded=true, currentSet=true, forceAccess=true]
packetMarker={}
currentEvent=
finalEvent=
unfilteredProcessedPackets=com.comphenix.protocol.injector.netty.PacketFilterQueue@698a0c51
vanillaDecoder=net.minecraft.network.PacketDecoder@7e345a9c
vanillaEncoder=net.minecraft.network.PacketEncoder@5c98467d
finishQueue=[]
channelListener=com.comphenix.protocol.injector.netty.ProtocolInjector@218b1a03
processor=com.comphenix.protocol.injector.NetworkProcessor@c098bc6
injected=true
closed=false
cumulation=PooledUnsafeDirectByteBuf(ridx: 34, widx: 34, cap: 34)
cumulator=io.netty.handler.codec.ByteToMessageDecoder$1@5cea7b51
singleDecode=false
first=true
firedChannelRead=true
selfFiredChannelRead=true
decodeState=1
discardAfterReads=16
numReads=0
added=true
]
Version:
ProtocolLib v4.8.0
Java Version:
17
Server:
git-Paper-372 (MC: 1.19.3)

This is fixed in the latest dev builds. Find them here: https://ci.dmulloy2.net/job/ProtocolLib/