[08:52:29 ERROR]: [ProtocolLib] INTERNAL ERROR: Unable to intercept a read client packet.
If this problem hasn't already been reported, please open a ticket
at https://github.com/dmulloy2/ProtocolLib/issues with the following data:
Stack Trace:
java.lang.RuntimeException: Error occured while instancing generated class.
at com.comphenix.protocol.reflect.compiler.StructureCompiler.compile(StructureCompiler.java:249)
at com.comphenix.protocol.reflect.compiler.CompiledStructureModifier.withTarget(CompiledStructureModifier.java:132)
at com.comphenix.protocol.events.PacketContainer.(PacketContainer.java:139)
at com.comphenix.protocol.injector.netty.ProtocolInjector.onPacketReceiving(ProtocolInjector.java:324)
at com.comphenix.protocol.injector.netty.ChannelInjector.decode(ChannelInjector.java:593)
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:428)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at com.comphenix.protocol.injector.netty.ChannelInjector$2.channelRead(ChannelInjector.java:289)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:310)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:284)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:310)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:284)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.GeneratedConstructorAccessor49.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.comphenix.protocol.reflect.compiler.StructureCompiler.compile(StructureCompiler.java:233)
... 43 more
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_12_R1/PacketPlayInFlying$PacketPlayInPositionLook
at com.comphenix.protocol.reflect.compiler.CompiledStructure$net_minecraft_network_play_client_CPacketPlayer_PositionRotation$java_lang_Object.(Unknown Source)
... 47 more
Dump:
Parameters:
io.netty.buffer.PooledUnsafeDirectByteBuf@5f591de7[
memoryAddress=2309812555888
recyclerHandle=io.netty.util.Recycler$DefaultHandle@75de008c
chunk=Chunk(38ff9e63: 3%, 335872/16777216)
handle=4611686022722357256
memory=java.nio.DirectByteBuffer[pos=0 lim=16777216 cap=16777216]
offset=65584
length=34
maxLength=48
cache=io.netty.buffer.PoolThreadCache@62ea89c3
tmpNioBuf=
allocator=PooledByteBufAllocator(directByDefault: true)
refCnt=1
readerIndex=34
writerIndex=34
markedReaderIndex=0
markedWriterIndex=0
maxCapacity=2147483647
]
manager:
com.comphenix.protocol.injector.PacketFilterManager@fadc32c[
unhookTask=com.comphenix.protocol.injector.DelayedSingleTask@39bff78b
packetListeners=[PacketAdapter[plugin=Alice, sending=ListeningWhitelist[priority=MONITOR, packets=[RESOURCE_PACK_SEND[class=PacketPlayOutResourcePackSend, id=60], HELD_ITEM_SLOT[class=PacketPlayInHeldItemSlot, id=37], POSITION[class=PacketPlayOutPosition, id=56], SET_CREATIVE_SLOT[class=PacketPlayInSetCreativeSlot, id=40], BLOCK_DIG[class=PacketPlayInBlockDig, id=26], ENTITY_ACTION[class=PacketPlayInEntityAction, id=27], STEER_VEHICLE[class=PacketPlayInSteerVehicle, id=28], RECIPE_DISPLAYED[class=PacketPlayInRecipeDisplayed, id=31], ARM_ANIMATION[class=PacketPlayInArmAnimation, id=44], TRANSACTION[class=PacketPlayOutTransaction, id=246], SPECTATE[class=PacketPlayInSpectate, id=45], USE_ITEM[class=PacketPlayInUseItem, id=46], BLOCK_PLACE[class=PacketPlayInBlockPlace, id=47], ABILITIES[class=PacketPlayOutAbilities, id=50], EXPLOSION[class=PacketPlayOutExplosion, id=28], CHAT[class=PacketPlayInChat, id=3], CLIENT_COMMAND[class=PacketPlayInClientCommand, id=4], SETTINGS[class=PacketPlayInSettings, id=5], WINDOW_CLICK[class=PacketPlayInWindowClick, id=8], CLOSE_WINDOW[class=PacketPlayInCloseWindow, id=9], KEEP_ALIVE[class=PacketPlayOutKeepAlive, id=33], POSITION_LOOK[class=PacketPlayInPositionLook, id=18], LOOK[class=PacketPlayInLook, id=19], VEHICLE_MOVE[class=PacketPlayInVehicleMove, id=21], ENTITY_VELOCITY[class=PacketPlayOutEntityVelocity, id=79], HELD_ITEM_SLOT[class=PacketPlayOutHeldItemSlot, id=72], ABILITIES[class=PacketPlayInAbilities, id=25], CUSTOM_PAYLOAD[class=PacketPlayInCustomPayload, id=10], USE_ENTITY[class=PacketPlayInUseEntity, id=13], KEEP_ALIVE[class=PacketPlayInKeepAlive, id=15], POSITION[class=PacketPlayInPosition, id=17]], gamephase=PLAYING, options=[]], receiving=ListeningWhitelist[priority=MONITOR, packets=[RESOURCE_PACK_SEND[class=PacketPlayOutResourcePackSend, id=60], HELD_ITEM_SLOT[class=PacketPlayInHeldItemSlot, id=37], POSITION[class=PacketPlayOutPosition, id=56], SET_CREATIVE_SLOT[class=PacketPlayInSetCreativeSlot, id=40], BLOCK_DIG[class=PacketPlayInBlockDig, id=26], ENTITY_ACTION[class=PacketPlayInEntityAction, id=27], STEER_VEHICLE[class=PacketPlayInSteerVehicle, id=28], RECIPE_DISPLAYED[class=PacketPlayInRecipeDisplayed, id=31], ARM_ANIMATION[class=PacketPlayInArmAnimation, id=44], TRANSACTION[class=PacketPlayOutTransaction, id=246], SPECTATE[class=PacketPlayInSpectate, id=45], USE_ITEM[class=PacketPlayInUseItem, id=46], BLOCK_PLACE[class=PacketPlayInBlockPlace, id=47], ABILITIES[class=PacketPlayOutAbilities, id=50], EXPLOSION[class=PacketPlayOutExplosion, id=28], CHAT[class=PacketPlayInChat, id=3], CLIENT_COMMAND[class=PacketPlayInClientCommand, id=4], SETTINGS[class=PacketPlayInSettings, id=5], WINDOW_CLICK[class=PacketPlayInWindowClick, id=8], CLOSE_WINDOW[class=PacketPlayInCloseWindow, id=9], KEEP_ALIVE[class=PacketPlayOutKeepAlive, id=33], POSITION_LOOK[class=PacketPlayInPositionLook, id=18], LOOK[class=PacketPlayInLook, id=19], VEHICLE_MOVE[class=PacketPlayInVehicleMove, id=21], ENTITY_VELOCITY[class=PacketPlayOutEntityVelocity, id=79], HELD_ITEM_SLOT[class=PacketPlayOutHeldItemSlot, id=72], ABILITIES[class=PacketPlayInAbilities, id=25], CUSTOM_PAYLOAD[class=PacketPlayInCustomPayload, id=10], USE_ENTITY[class=PacketPlayInUseEntity, id=13], KEEP_ALIVE[class=PacketPlayInKeepAlive, id=15], POSITION[class=PacketPlayInPosition, id=17]], gamephase=PLAYING, options=[]]]]
packetInjector=com.comphenix.protocol.injector.netty.ProtocolInjector$5@2000d5a1
playerInjection=com.comphenix.protocol.injector.netty.ProtocolInjector$4@4181c9fc
inputBufferedPackets=[]
recievedListeners=com.comphenix.protocol.injector.SortedPacketListenerList@2054c643
sendingListeners=com.comphenix.protocol.injector.SortedPacketListenerList@66117e6d
hasClosed=false
classLoader=org.bukkit.plugin.java.PluginClassLoader@4f4729d3
reporter=com.comphenix.protocol.ProtocolLib$1@401a12d3
server=CraftServer{serverName=Mohist,serverVersion=git-Mohist-1.12.2-258,minecraftVersion=1.12.2}
library=ProtocolLib v4.7.0
asyncFilterManager=com.comphenix.protocol.async.AsyncFilterManager@97b547b
knowsServerPackets=true
knowsClientPackets=true
phaseLoginCount=0
phasePlayingCount=3
packetCreation=true
nettyInjector=com.comphenix.protocol.injector.netty.ProtocolInjector@77c0d3db
pluginVerifier=com.comphenix.protocol.injector.PluginVerifier@36fc69c5
hasRecycleDistance=true
minecraftVersion=(MC: 1.12.2)
debug=false
]
Sender:
com.comphenix.protocol.injector.netty.ChannelInjector@77a3319[
decodeBuffer=protected void net.minecraft.network.NettyPacketDecoder.decode(io.netty.channel.ChannelHandlerContext,io.netty.buffer.ByteBuf,java.util.List) throws java.lang.Exception
encodeBuffer=protected void net.minecraft.network.NettyPacketEncoder.encode(io.netty.channel.ChannelHandlerContext,java.lang.Object,io.netty.buffer.ByteBuf) throws java.lang.Exception
factory=com.comphenix.protocol.injector.netty.InjectionFactory@7f54cef8
player=CraftPlayer{name=NIKO4685}
updated=CraftPlayer{name=NIKO4685}
playerName=NIKO4685
playerConnection=net.minecraftforge.fml.common.network.handshake.NetworkDispatcher$1@e7b94c2
networkManager=net.minecraft.network.NetworkManager@5b1c6689
originalChannel=[id: 0xa8b25eb7, L:/127.0.0.1:25565 - R:/127.0.0.1:59062]
channelField=VolatileField [accessor=DefaultFieldAccessor [field=public io.netty.channel.Channel net.minecraft.network.NetworkManager.field_150746_k], container=net.minecraft.network.NetworkManager@5b1c6689, previous=[id: 0xa8b25eb7, L:/127.0.0.1:25565 - R:/127.0.0.1:59062], current=com.comphenix.protocol.injector.netty.ChannelInjector$3@708b260e, previousLoaded=true, currentSet=true, forceAccess=true]
packetMarker={}
currentEvent=
finalEvent=
unfilteredProcessedPackets=com.comphenix.protocol.injector.netty.PacketFilterQueue@365d28d4
vanillaDecoder=net.minecraft.network.NettyPacketDecoder@58329cab
vanillaEncoder=net.minecraft.network.NettyPacketEncoder@ec6f083
finishQueue=[]
channelListener=com.comphenix.protocol.injector.netty.ProtocolInjector@77c0d3db
processor=com.comphenix.protocol.injector.NetworkProcessor@78908bb5
injected=true
closed=false
cumulation=PooledUnsafeDirectByteBuf(ridx: 34, widx: 34, cap: 34)
cumulator=io.netty.handler.codec.ByteToMessageDecoder$1@340b97c8
singleDecode=false
decodeWasNull=false
first=true
decodeState=1
discardAfterReads=16
numReads=0
added=true
]
Version:
ProtocolLib v4.7.0
Java Version:
1.8.0_252
Server:
git-Mohist-1.12.2-258 (MC: 1.12.2)

The official stance of ProtocolLib is to not use Mohist. They've done some shady stuff with plugin jars which you can read more about here: https://essentialsx.net/do-not-use-mohist.html