Solved NullReferenceException in custom command

Hello. Immediately apologize for my English. I use a translator.
Can you tell what could be the reason?

Code:

[Oxide] 12:04 [Error] Failed to call hook 'CommandConsoleAuth' on plugin 'FriendAuthorization v1.0.0' (NullReferenceException: Object reference not set to an instance of an object)
[Oxide] 12:04 [Debug]   at Oxide.Plugins.FriendAuthorization.<AuthorizationCodeLocks>m__2 (.CodeLock codeLock, .BasePlayer friend) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.FriendAuthorization.Authorization[CodeLock] (.BasePlayer player, System.Collections.Generic.List`1 entities, System.String completionLang, System.String noEntityLang, System.Action`2 execute) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.FriendAuthorization.AuthorizationCodeLocks (.BasePlayer player) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.FriendAuthorization.CommandConsoleAuth (.Arg arg) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.FriendAuthorization.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (HookMethod method, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x00000] in <filename unknown>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String name, System.Object[] args) [0x00000] in <filename unknown>:0

Code:

[ConsoleCommand("auth")]
        private void CommandConsoleAuth(ConsoleSystem.Arg arg)
        {
            if (arg.connection == null || arg.Player() == null || !arg.HasArgs()) return;            switch (arg.Args[0].ToLower())
            {
                case "a.cupboard":
                    AuthorizationCupboard(arg.Player());
                    return;
                case "a.autoturret":
                    AuthorizationAutoTurret(arg.Player());
                    return;
                case "a.codelock":
                    AuthorizationCodeLocks(arg.Player());
                    return;
                case "d.cupboard":
                    DeauthorizationCupboard(arg.Player());
                    return;
                case "d.autoturret":
                    DeauthorizationAutoTurret(arg.Player());
                    return;
                case "d.codelock":
                    DeauthorizationCodeLocks(arg.Player());
                    return;
            }
        }

 

Thank you. And could you show me how to do it? Just not my plugin, and writing plugins, I am not strong.

 

--snipped--

 

Thank you. If possible, delete the topic.