[22:19:19 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'mmocore' in plugin MMOCore v1.9-SNAPSHOT
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.v1_18_R1.CraftServer.dispatchCommand(CraftServer.java:897) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.handleCommand(ServerGamePacketListenerImpl.java:2293) ~[?:?]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.handleChat(ServerGamePacketListenerImpl.java:2104) ~[?:?]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.handleChat(ServerGamePacketListenerImpl.java:2085) ~[?:?]
        at net.minecraft.network.protocol.game.ServerboundChatPacket.handle(ServerboundChatPacket.java:46) ~[?:?]
        at net.minecraft.network.protocol.game.ServerboundChatPacket.a(ServerboundChatPacket.java:6) ~[?:?]
        at net.minecraft.network.protocol.PacketUtils.lambda$ensureRunningOnSameThread$1(PacketUtils.java:56) ~[?:?]
        at net.minecraft.server.TickTask.run(TickTask.java:18) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:149) ~[?:?]
        at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:23) ~[?:?]
        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1413) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.server.MinecraftServer.c(MinecraftServer.java:189) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:122) ~[?:?]
        at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1391) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1384) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:132) ~[?:?]
        at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:1362) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1268) ~[paper-1.18.1.jar:git-Paper-187]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:317) ~[paper-1.18.1.jar:git-Paper-187]
        at java.lang.Thread.run(Thread.java:833) ~[?:?]
Caused by: java.lang.IllegalArgumentException: Skill is active
        at org.apache.commons.lang.Validate.isTrue(Validate.java:136) ~[commons-lang-2.6.jar:2.6]
        at net.Indyuce.mmocore.skill.ClassSkill.toPassive(ClassSkill.java:117) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.api.player.stats.PlayerStats.updateStats(PlayerStats.java:110) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.api.player.PlayerData.giveExperience(PlayerData.java:582) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.api.player.PlayerData.giveExperience(PlayerData.java:521) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.api.player.PlayerData.giveLevels(PlayerData.java:318) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.command.rpg.admin.LevelCommandTreeNode.lambda$new$0(LevelCommandTreeNode.java:25) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at net.Indyuce.mmocore.command.rpg.admin.LevelCommandTreeNode$ActionCommandTreeNode.execute(LevelCommandTreeNode.java:66) ~[MMOCore-1.9-SNAPSHOT (9).jar:?]
        at io.lumine.mythic.lib.commands.mmolib.api.CommandTreeRoot.onCommand(CommandTreeRoot.java:42) ~[MythicLib-1.3-R28-SNAPSHOT.jar:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?]
        ... 21 more