[01:45:57 INFO]: Tsayoko issued server command: /citizensgui
[01:45:57 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'citizensgui' in plugin CitizensGUI v1.1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[patched_1.15.2.jar:git-Paper-261]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[patched_1.15.2.jar:git-Paper-261]
        at org.bukkit.craftbukkit.v1_15_R1.CraftServer.dispatchCommand(CraftServer.java:760) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.PlayerConnection.handleCommand(PlayerConnection.java:1852) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.PlayerConnection.a(PlayerConnection.java:1660) ~[patched_1.15.2.jar:git-Paper-261]
        at xuan.cat.PacketEventCatAPI.code.v1_15_R1.CodeExtendPlayerConnection.packetIn(CodeExtendPlayerConnection.java:704) ~[?:?]
        at xuan.cat.PacketEventCatAPI.code.v1_15_R1.CodeExtendPlayerConnection.packetIn(CodeExtendPlayerConnection.java:564) ~[?:?]
        at xuan.cat.PacketEventCatAPI.code.v1_15_R1.CodeExtendPlayerConnection.a(CodeExtendPlayerConnection.java:53) ~[?:?]
        at net.minecraft.server.v1_15_R1.PacketPlayInChat.a(PacketPlayInChat.java:47) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.PacketPlayInChat.a(PacketPlayInChat.java:5) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:23) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.TickTask.run(SourceFile:18) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.MinecraftServer.ba(MinecraftServer.java:1093) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.MinecraftServer.executeNext(MinecraftServer.java:1086) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.awaitTasks(IAsyncTaskHandler.java:119) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.MinecraftServer.sleepForTick(MinecraftServer.java:1047) ~[patched_1.15.2.jar:git-Paper-261]
        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:962) ~[patched_1.15.2.jar:git-Paper-261]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_201]
Caused by: java.lang.NullPointerException
        at fr.ender_griefeur99.citizensgui.CitizensListGUI.itemMenu(CitizensListGUI.java:145) ~[?:?]
        at fr.ender_griefeur99.citizensgui.CitizensListGUI.setItems(CitizensListGUI.java:85) ~[?:?]
        at fr.ender_griefeur99.citizensgui.CitizensListGUI.<init>(CitizensListGUI.java:73) ~[?:?]
        at fr.ender_griefeur99.citizensgui.Main.onCommand(Main.java:38) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[patched_1.15.2.jar:git-Paper-261]
        ... 20 more