here`s log

[10:37:43 INFO]: [ProtocolLib] Loading server plugin ProtocolLib v5.1.0
[10:37:43 WARN]: [ProtocolLib] Version (MC: 1.21.0) has not yet been tested! Proceed with caution.
[10:37:45 ERROR]: [ProtocolLib] Assuming package version: v1_21_R1
[10:37:45 ERROR]: [ProtocolLib] INTERNAL ERROR: Cannot load ProtocolLib.
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.IllegalArgumentException: Unable to find a field that matches {modifiers=[required: 10000, banned: 1000], type={ type input instanceof interface java.util.Map }}
at ProtocolLib.jar//com.comphenix.protocol.reflect.FuzzyReflection.getField(FuzzyReflection.java:352)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.createNewRegister(PacketRegistry.java:168)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.initialize(PacketRegistry.java:292)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.getClientPacketTypes(PacketRegistry.java:327)
at ProtocolLib.jar//com.comphenix.protocol.injector.PacketFilterManager.(PacketFilterManager.java:120)
at ProtocolLib.jar//com.comphenix.protocol.injector.PacketFilterBuilder.build(PacketFilterBuilder.java:121)
at ProtocolLib.jar//com.comphenix.protocol.ProtocolLib.onLoad(ProtocolLib.java:183)
at io.papermc.paper.plugin.storage.ServerPluginProviderStorage.processProvided(ServerPluginProviderStorage.java:59)
at io.papermc.paper.plugin.storage.ServerPluginProviderStorage.processProvided(ServerPluginProviderStorage.java:18)
at io.papermc.paper.plugin.storage.SimpleProviderStorage.enter(SimpleProviderStorage.java:39)
at io.papermc.paper.plugin.entrypoint.LaunchEntryPointHandler.enter(LaunchEntryPointHandler.java:40)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:535)
at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:290)
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1157)
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:329)
at java.base/java.lang.Thread.run(Thread.java:1583)
Dump:
Parameters:
[NULL]
Sender:
com.comphenix.protocol.ProtocolLib@63c07a8a[
statistics=
packetTask=
tickCounter=0
configExpectedMod=-1
updater=com.comphenix.protocol.updater.SpigotUpdater@19b5dcd4
redirectHandler=
scheduler=com.comphenix.protocol.scheduler.DefaultScheduler@7941f142
commandProtocol=
commandPacket=
commandFilter=
packetLogging=
skipDisable=false
isEnabled=false
loader=io.papermc.paper.plugin.manager.DummyBukkitPluginLoader@3025db76
server=CraftServer{serverName=Paper,serverVersion=1.21-39-aa8d38d,minecraftVersion=1.21}
file=plugins/.paper-remapped/ProtocolLib.jar
description=org.bukkit.plugin.PluginDescriptionFile@26b85891
pluginMeta=org.bukkit.plugin.PluginDescriptionFile@26b85891
dataFolder=plugins/ProtocolLib
classLoader=PluginClassLoader{plugin=ProtocolLib v5.1.0, pluginEnabled=false, url=plugins/.paper-remapped/ProtocolLib.jar}
naggable=true
newConfig=YamlConfiguration[path='', root='YamlConfiguration']
configFile=plugins/ProtocolLib/config.yml
logger=com.destroystokyo.paper.utils.PaperPluginLogger@59ab8ffd
lifecycleEventManager=io.papermc.paper.plugin.lifecycle.event.PaperLifecycleEventManager@4a560c4f
allowsLifecycleRegistration=true
]
Version:
ProtocolLib v5.1.0
Java Version:
21.0.3
Server:
1.21-39-aa8d38d (MC: 1.21)

[10:37:45 INFO]: [pv-addon-lavaplayer-lib] Loading server plugin pv-addon-lavaplayer-lib v1.0.9
[10:37:45 INFO]: [pv-addon-groups] Loading server plugin pv-addon-groups v1.0.3
[10:37:45 INFO]: [AuthMe] Loading server plugin AuthMe v5.6.0-bCUSTOM
[10:37:45 INFO]: [pv-addon-sculk] Loading server plugin pv-addon-sculk v1.0.0
[10:37:45 INFO]: [pv-addon-discs] Loading server plugin pv-addon-discs v1.0.6
[10:37:45 INFO]: Server permissions file permissions.yml is empty, ignoring it
[10:37:45 INFO]: [PlasmoVoice] Enabling PlasmoVoice v2.0.10
[10:37:46 INFO]: [PlasmoVoice] pv-addon-groups v1.0.3 by KPidS loaded
[10:37:46 INFO]: [PlasmoVoice] pv-addon-lavaplayer-lib v1.0.9 by Apehum loaded
[10:37:46 INFO]: [PlasmoVoice] pv-addon-sculk v1.0.0 by Apehum loaded
[10:37:46 INFO]: [PlasmoVoice] pv-addon-discs v1.0.6 by KPidS loaded
[10:37:46 INFO]: [PlasmoVoice] UDP server is started on /[0:0:0:0:0:0:0:0]:25565
[10:37:46 INFO]: [ProtocolLib] Enabling ProtocolLib v5.1.0
[10:37:46 ERROR]: ******************************************************
[10:37:46 ERROR]: *** ProtocolLib does not support plugin reloaders! ***
[10:37:46 ERROR]: *** Please use the built-in reload command! ***
[10:37:46 ERROR]: ******************************************************
[10:37:46 INFO]: [ProtocolLib] Disabling ProtocolLib v5.1.0
[10:37:46 INFO]: [pv-addon-lavaplayer-lib] Enabling pv-addon-lavaplayer-lib v1.0.9
[10:37:46 INFO]: [pv-addon-groups] Enabling pv-addon-groups v1.0.3
[10:37:46 INFO]: [pv-addon-sculk] Enabling pv-addon-sculk v1.0.0
[10:37:46 INFO]: [pv-addon-discs] Enabling pv-addon-discs v1.0.6
[10:37:47 ERROR]: Error occurred while enabling pv-addon-discs v1.0.6 (Is it up to date?)
java.lang.NoClassDefFoundError: com/comphenix/protocol/ProtocolLibrary
at pv-addon-discs-1.0.6.jar/su.plo.voice.discs.DiscsPlugin.onEnable(DiscsPlugin.kt:90) ~[pv-addon-discs-1.0.6.jar:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:288) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:202) ~[paper-1.21.jar:1.21-39-aa8d38d]
at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[paper-1.21.jar:1.21-39-aa8d38d]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:520) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:629) ~[paper-1.21.jar:1.21-39-aa8d38d]
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:578) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:291) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1157) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:329) ~[paper-1.21.jar:1.21-39-aa8d38d]
at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: com.comphenix.protocol.ProtocolLibrary
at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:197) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:164) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[?:?]
... 11 more

How about updating? ;)

[11:30:18 INFO]: Paper: Using OpenSSL 1.1.x (Linux x86_64) cipher from Velocity.
[11:30:18 INFO]: [PlasmoVoice] Loading server plugin PlasmoVoice v2.0.10
[11:30:18 INFO]: [ProtocolLib] Loading server plugin ProtocolLib v5.2.0-SNAPSHOT-679
[11:30:18 WARN]: [ProtocolLib] Version (MC: 1.21.0) has not yet been tested! Proceed with caution.
[11:30:20 ERROR]: [ProtocolLib] Assuming package version: v1_21_R1
[11:30:20 ERROR]: [ProtocolLib] INTERNAL ERROR: Cannot load ProtocolLib.
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.IllegalArgumentException: Unable to find a field that matches {modifiers=[required: 10000, banned: 1000], type={ type input instanceof interface java.util.Map }}
at ProtocolLib.jar//com.comphenix.protocol.reflect.FuzzyReflection.getField(FuzzyReflection.java:352)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.createNewRegister(PacketRegistry.java:183)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.initialize(PacketRegistry.java:334)
at ProtocolLib.jar//com.comphenix.protocol.injector.packet.PacketRegistry.getClientPacketTypes(PacketRegistry.java:369)
at ProtocolLib.jar//com.comphenix.protocol.injector.PacketFilterManager.(PacketFilterManager.java:120)
at ProtocolLib.jar//com.comphenix.protocol.injector.PacketFilterBuilder.build(PacketFilterBuilder.java:121)
at ProtocolLib.jar//com.comphenix.protocol.ProtocolLib.onLoad(ProtocolLib.java:183)
at io.papermc.paper.plugin.storage.ServerPluginProviderStorage.processProvided(ServerPluginProviderStorage.java:59)
at io.papermc.paper.plugin.storage.ServerPluginProviderStorage.processProvided(ServerPluginProviderStorage.java:18)
at io.papermc.paper.plugin.storage.SimpleProviderStorage.enter(SimpleProviderStorage.java:39)
at io.papermc.paper.plugin.entrypoint.LaunchEntryPointHandler.enter(LaunchEntryPointHandler.java:40)
at org.bukkit.craftbukkit.CraftServer.loadPlugins(CraftServer.java:535)
at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:290)
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1157)
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:329)
at java.base/java.lang.Thread.run(Thread.java:1583)
Dump:
Parameters:
[NULL]
Sender:
com.comphenix.protocol.ProtocolLib@547f474a[
statistics=
packetTask=
tickCounter=0
configExpectedMod=-1
updater=com.comphenix.protocol.updater.SpigotUpdater@2dd7b278
redirectHandler=
scheduler=com.comphenix.protocol.scheduler.DefaultScheduler@33ce59f
commandProtocol=
commandPacket=
commandFilter=
packetLogging=
skipDisable=false
isEnabled=false
loader=io.papermc.paper.plugin.manager.DummyBukkitPluginLoader@3bbda255
server=CraftServer{serverName=Paper,serverVersion=1.21-39-aa8d38d,minecraftVersion=1.21}
file=plugins/.paper-remapped/ProtocolLib.jar
description=org.bukkit.plugin.PluginDescriptionFile@a64abe8
pluginMeta=org.bukkit.plugin.PluginDescriptionFile@a64abe8
dataFolder=plugins/ProtocolLib
classLoader=PluginClassLoader{plugin=ProtocolLib v5.2.0-SNAPSHOT-679, pluginEnabled=false, url=plugins/.paper-remapped/ProtocolLib.jar}
naggable=true
newConfig=YamlConfiguration[path='', root='YamlConfiguration']
configFile=plugins/ProtocolLib/config.yml
logger=com.destroystokyo.paper.utils.PaperPluginLogger@1f05fa68
lifecycleEventManager=io.papermc.paper.plugin.lifecycle.event.PaperLifecycleEventManager@72310419
allowsLifecycleRegistration=true
]
Version:
ProtocolLib v5.2.0-SNAPSHOT-679
Java Version:
21.0.3
Server:
1.21-39-aa8d38d (MC: 1.21)

[11:30:20 INFO]: [pv-addon-lavaplayer-lib] Loading server plugin pv-addon-lavaplayer-lib v1.0.9
[11:30:20 INFO]: [pv-addon-groups] Loading server plugin pv-addon-groups v1.0.3
[11:30:20 INFO]: [AuthMe] Loading server plugin AuthMe v5.6.0-bCUSTOM
[11:30:20 INFO]: [pv-addon-sculk] Loading server plugin pv-addon-sculk v1.0.0
[11:30:20 INFO]: [pv-addon-discs] Loading server plugin pv-addon-discs v1.0.6
[11:30:20 INFO]: Server permissions file permissions.yml is empty, ignoring it
[11:30:20 INFO]: [PlasmoVoice] Enabling PlasmoVoice v2.0.10
[11:30:21 INFO]: [PlasmoVoice] pv-addon-groups v1.0.3 by KPidS loaded
[11:30:21 INFO]: [PlasmoVoice] pv-addon-lavaplayer-lib v1.0.9 by Apehum loaded
[11:30:21 INFO]: [PlasmoVoice] pv-addon-sculk v1.0.0 by Apehum loaded
[11:30:21 INFO]: [PlasmoVoice] pv-addon-discs v1.0.6 by KPidS loaded
[11:30:21 INFO]: [PlasmoVoice] UDP server is started on /[0:0:0:0:0:0:0:0]:25565
[11:30:21 INFO]: [ProtocolLib] Enabling ProtocolLib v5.2.0-SNAPSHOT-679
[11:30:21 ERROR]: ******************************************************
[11:30:21 ERROR]: *** ProtocolLib does not support plugin reloaders! ***
[11:30:21 ERROR]: *** Please use the built-in reload command! ***
[11:30:21 ERROR]: ******************************************************
[11:30:21 INFO]: [ProtocolLib] Disabling ProtocolLib v5.2.0-SNAPSHOT-679
[11:30:21 INFO]: [pv-addon-lavaplayer-lib] Enabling pv-addon-lavaplayer-lib v1.0.9
[11:30:21 INFO]: [pv-addon-groups] Enabling pv-addon-groups v1.0.3
[11:30:21 INFO]: [pv-addon-sculk] Enabling pv-addon-sculk v1.0.0
[11:30:21 INFO]: [pv-addon-discs] Enabling pv-addon-discs v1.0.6
[11:30:22 ERROR]: Error occurred while enabling pv-addon-discs v1.0.6 (Is it up to date?)
java.lang.NoClassDefFoundError: com/comphenix/protocol/ProtocolLibrary
at pv-addon-discs-1.0.6.jar/su.plo.voice.discs.DiscsPlugin.onEnable(DiscsPlugin.kt:90) ~[pv-addon-discs-1.0.6.jar:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:288) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:202) ~[paper-1.21.jar:1.21-39-aa8d38d]
at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[paper-1.21.jar:1.21-39-aa8d38d]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:520) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:629) ~[paper-1.21.jar:1.21-39-aa8d38d]
at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:578) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:291) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1157) ~[paper-1.21.jar:1.21-39-aa8d38d]
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:329) ~[paper-1.21.jar:1.21-39-aa8d38d]
at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.ClassNotFoundException: com.comphenix.protocol.ProtocolLibrary
at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:197) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:164) ~[paper-api-1.21-R0.1-SNAPSHOT.jar:?]
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526) ~[?:?]
... 11 more
[11:30:22 INFO]: [pv-addon-discs] Disabling pv-addon-discs v1.0.6

Should be fixed in the latest dev build so please use the latest dev build and try again: https://ci.dmulloy2.net/job/ProtocolLib/