kb sound not working

[m4kii420]

/npc property set <NPC_NAME> player_knockback_sound_name ITEM_TRIDENT_HIT_GROUND

ERROR:

[10:23:26 INFO]: NicotineAbuser issued server command: /npc property set diapot-ffa player_knockback_sound_name ITEM_TRIDENT_HIT_GROUND
[10:23:26 WARN]: java.lang.NullPointerException: Cannot invoke "lol.pyr.znpcsplus.libraries.command.common.parse.CommonParserType.parse(java.util.Deque)" because "parser" is null
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.common.command.CommonCommandContext.parse(CommonCommandContext.java:59)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.commands.property.PropertySetCommand.run(PropertySetCommand.java:140)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.commands.property.PropertySetCommand.run(PropertySetCommand.java:31)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.common.command.CommonMultiCommand.run(CommonMultiCommand.java:23)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.common.command.CommonMultiCommand.run(CommonMultiCommand.java:10)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.common.command.CommonMultiCommand.run(CommonMultiCommand.java:23)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.adventure.command.MultiCommand.run(MultiCommand.java:7)
[10:23:26 WARN]:        at ZNPCsPlus-2.1.0-SNAPSHOT (5).jar//lol.pyr.znpcsplus.libraries.command.adventure.command.CommandAdapter.onCommand(CommandAdapter.java:27)
[10:23:26 WARN]:        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45)
[10:23:26 WARN]:        at io.papermc.paper.command.brigadier.bukkit.BukkitCommandNode$BukkitBrigCommand.run(BukkitCommandNode.java:83)
[10:23:26 WARN]:        at com.mojang.brigadier.context.ContextChain.runExecutable(ContextChain.java:73)
[10:23:26 WARN]:        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:30)
[10:23:26 WARN]:        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:13)
[10:23:26 WARN]:        at net.minecraft.commands.execution.UnboundEntryAction.lambda$bind$0(UnboundEntryAction.java:8)
[10:23:26 WARN]:        at net.minecraft.commands.execution.CommandQueueEntry.execute(CommandQueueEntry.java:5)
[10:23:26 WARN]:        at net.minecraft.commands.execution.ExecutionContext.runCommandQueue(ExecutionContext.java:105)
[10:23:26 WARN]:        at net.minecraft.commands.Commands.executeCommandInContext(Commands.java:451)
[10:23:26 WARN]:        at net.minecraft.commands.Commands.performCommand(Commands.java:357)
[10:23:26 WARN]:        at net.minecraft.commands.Commands.performCommand(Commands.java:345)
[10:23:26 WARN]:        at net.minecraft.server.network.ServerGamePacketListenerImpl.performUnsignedChatCommand(ServerGamePacketListenerImpl.java:2313)
[10:23:26 WARN]:        at net.minecraft.server.network.ServerGamePacketListenerImpl.lambda$handleChatCommand$12(ServerGamePacketListenerImpl.java:2286)
[10:23:26 WARN]:        at net.minecraft.server.TickTask.run(TickTask.java:18)
[10:23:26 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:155)
[10:23:26 WARN]:        at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:24)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1450)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:176)
[10:23:26 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:129)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1430)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1424)
[10:23:26 WARN]:        at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:139)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.managedBlock(MinecraftServer.java:1381)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:1389)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1266)
[10:23:26 WARN]:        at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:310)
[10:23:26 WARN]:        at java.base/java.lang.Thread.run(Thread.java:1570)