[13:50:00 ERROR]: Command exception: /mm items import 1 1
org.bukkit.command.CommandException: Unhandled exception executing command 'mm' in plugin MythicMobs v5.9.2-SNAPSHOT-39051f06
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[purpur-api-1.21.5-R0.1-SNAPSHOT.jar:?]
        at io.papermc.paper.command.brigadier.bukkit.BukkitCommandNode$BukkitBrigCommand.run(BukkitCommandNode.java:83) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at com.mojang.brigadier.context.ContextChain.runExecutable(ContextChain.java:73) ~[brigadier-1.3.10.jar:?]
        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:30) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.execution.tasks.ExecuteCommand.execute(ExecuteCommand.java:13) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.execution.UnboundEntryAction.lambda$bind$0(UnboundEntryAction.java:8) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.execution.CommandQueueEntry.execute(CommandQueueEntry.java:5) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.execution.ExecutionContext.runCommandQueue(ExecutionContext.java:105) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.Commands.executeCommandInContext(Commands.java:457) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.Commands.performCommand(Commands.java:365) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.Commands.performCommand(Commands.java:355) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.commands.Commands.performCommand(Commands.java:349) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.performUnsignedChatCommand(ServerGamePacketListenerImpl.java:2350) ~[purpur-1.21.5.jar:1.21.5-2
450-61d7f55]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.lambda$handleChatCommand$15(ServerGamePacketListenerImpl.java:2323) ~[purpur-1.21.5.jar:1.21.5-
2450-61d7f55]
        at net.minecraft.server.TickTask.run(TickTask.java:18) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:155) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:24) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1482) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:175) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:129) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1462) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1456) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:139) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.managedBlock(MinecraftServer.java:1413) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.waitUntilNextTick(MinecraftServer.java:1421) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1298) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:311) ~[purpur-1.21.5.jar:1.21.5-2450-61d7f55]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]
Caused by: java.lang.NullPointerException: Cannot invoke "org.bukkit.Material.getMaxStackSize()" because "this.material" is null
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.core.items.MythicItem.loadItem(MythicItem.java:478) ~[[神话怪物]MythicMobs-5.9.2--SHOT 5449.ja
r:?]
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.core.items.MythicItem.<init>(MythicItem.java:189) ~[[神话怪物]MythicMobs-5.9.2--SHOT 5449.jar:
?]
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.bukkit.commands.items.ImportCommand.onCommand(ImportCommand.java:73) ~[[神话怪物]MythicMobs-5.
9.2--SHOT 5449.jar:?]
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.bukkit.utils.commands.Command.onCommand(Command.java:64) ~[[神话怪物]MythicMobs-5.9.2--SHOT 54
49.jar:?]
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.bukkit.utils.commands.Command.onCommand(Command.java:55) ~[[神话怪物]MythicMobs-5.9.2--SHOT 54
49.jar:?]
        at [神话怪物]MythicMobs-5.9.2--SHOT 5449.jar/io.lumine.mythic.bukkit.utils.commands.Command.onCommand(Command.java:55) ~[[神话怪物]MythicMobs-5.9.2--SHOT 54
49.jar:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[purpur-api-1.21.5-R0.1-SNAPSHOT.jar:?]
        ... 27 more