Stack Trace:
java.lang.IllegalArgumentException: Unable to find a field that matches {modifiers=[required: 0, banned: 0], type={
fields=[{modifiers=[required: 0, banned: 0], type=Exact class net.minecraft.world.entity.Entity}],
methods=[{modifiers=[required: 0, banned: 0], params=[{Type: Exact class java.lang.String, Index: null}], paramCount=1}],
constructors=[{modifiers=[required: 0, banned: 0], params=[{Type: class net.minecraft.server.dedicated.DedicatedServer instanceof input, Index: 0}, {Type: class net.minecraft.world.entity.Entity instanceof input, Index: 2}], paramCount=3}]
}}
at com.comphenix.protocol.reflect.FuzzyReflection.getField(FuzzyReflection.java:460)
at com.comphenix.protocol.utility.MinecraftReflection.getPlayerConnectionClass(MinecraftReflection.java:1065)
at com.comphenix.protocol.utility.MinecraftReflection.getNetworkManagerClass(MinecraftReflection.java:1082)
at com.comphenix.protocol.utility.MinecraftReflection.getEnumProtocolClass(MinecraftReflection.java:758)
at com.comphenix.protocol.injector.netty.ProtocolRegistry.(ProtocolRegistry.java:58)
at com.comphenix.protocol.injector.netty.NettyProtocolRegistry.(NettyProtocolRegistry.java:43)
at com.comphenix.protocol.injector.packet.PacketRegistry.initialize(PacketRegistry.java:54)
at com.comphenix.protocol.injector.packet.PacketRegistry.getClientPacketTypes(PacketRegistry.java:112)
at com.comphenix.protocol.injector.PacketFilterManager.(PacketFilterManager.java:211)
at com.comphenix.protocol.injector.PacketFilterBuilder.buildInternal(PacketFilterBuilder.java:185)
at com.comphenix.protocol.injector.PacketFilterBuilder.build(PacketFilterBuilder.java:177)
at com.comphenix.protocol.ProtocolLib.onLoad(ProtocolLib.java:198)
at org.bukkit.craftbukkit.v1_17_R1.CraftServer.loadPlugins(CraftServer.java:399)
at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:276)
at net.minecraft.server.MinecraftServer.x(MinecraftServer.java:1126)
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:316)
at java.base/java.lang.Thread.run(Thread.java:831)
Dump:
Parameters:
[NULL]
Sender:
com.comphenix.protocol.ProtocolLib@37185586[
statistics=
backgroundCompiler=
packetTask=-1
tickCounter=0
unhookTask=com.comphenix.protocol.injector.DelayedSingleTask@4da2671d
configExpectedMod=-1
updater=com.comphenix.protocol.updater.SpigotUpdater@302da6f2
redirectHandler=
commandProtocol=
commandPacket=
commandFilter=
packetLogging=
skipDisable=false
isEnabled=false
loader=org.bukkit.plugin.java.JavaPluginLoader@5af86f17
server=CraftServer{serverName=Paper,serverVersion=git-Paper-83,minecraftVersion=1.17.1}
file=plugins/ProtocolLib.jar
description=org.bukkit.plugin.PluginDescriptionFile@71fda5de
dataFolder=plugins/ProtocolLib
classLoader=PluginClassLoader{plugin=ProtocolLib v4.6.0, pluginEnabled=false, url=plugins/ProtocolLib.jar}
naggable=true
newConfig=YamlConfiguration[path='', root='YamlConfiguration']
configFile=plugins/ProtocolLib/config.yml
logger=com.destroystokyo.paper.utils.PaperPluginLogger@35a3c562
]
Version:
ProtocolLib v4.6.0
Java Version:
16.0.1
Server:
git-Paper-83 (MC: 1.17.1)

Version Info
4.6.0 1.17.1

Same problem here

Yep same here too.

Please update to the latest dev build (4.7.1) in order to run protocollib on a 1.17+ server. The download is available here

This is fixed in the 4.7.0 release. Find it here: https://github.com/dmulloy2/ProtocolLib/releases/tag/4.7.0