10:59 [Error] Failed to call hook 'GiveCommand' on plugin 'Give v3.0.2' (NullReferenceException: Object reference not set to an instance of an object) at CodeHatch.Common.PlayerExtensions.SendMessage (CodeHatch.Engine.Networking.Player player, System.String message) [0x00000] in :0 at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsPlayer.Message (System.String message, System.String prefix, System.Object[] args) [0x00000] in :0 at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsPlayer.Reply (System.String message) [0x00000] in :0 at Oxide.Plugins.Give.Message (IPlayer player, System.String key, System.Object[] args) [0x00000] in :0 at Oxide.Plugins.Give.GiveCommand (IPlayer player, System.String command, System.String[] args) [0x00000] in :0 at Oxide.Plugins.Give.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00000] in :0 at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00000] in :0 at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x00000] in :0 at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00000] in :0

That isn't an error with this plugin most likely, that would be with the message handling in Oxide for RoK.

When did the error happen and how did you trigger it?

I think it was after the last game update. I did a fresh installation of server and uMod but it wasn't help me.

When was the command used to give the item? I'm thinking that the player was not connected when the give was attempted.

I was using Server2 player to give items (through RCON, isServer check commented), but it was working before the R22 update.

Sounds like the server may no longer have a Player object tied to it then.

Is there a way to make RCON compatibility to give items w/o player object?

Yes, should be an issue.

I did create a new thread for this issue. Please, leave info about any progress in this direction. 

New thread is unnecessary, it isn't even an issue with this plugin as mentioned above.

Please fix it. Looks like this error makes many problems like:

18:25 [Info] [CommandLog] Server2 (9999999999) ran command: o.reload TimedExecute
18:25 [Error] Failed to call hook 'IOnServerCommand' on plugin 'ReignOfKingsCore v2.0.3832' (NullReferenceException: Object reference not set to an instance of an object)
  at CodeHatch.Common.PlayerExtensions.SendMessage (CodeHatch.Engine.Networking.Player player, System.String message) [0x00000] in <filename unknown>:0 
  at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsPlayer.Message (System.String message, System.String prefix, System.Object[] args) [0x00000] in <filename unknown>:0 
  at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsPlayer.Message (System.String message) [0x00000] in <filename unknown>:0 
  at Oxide.Core.Plugins.Plugin.CovalenceCommandCallback (IPlayer caller, System.String cmd, System.String[] args) [0x00000] in <filename unknown>:0 
  at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsCommandSystem.ChatCommandCallback (IPlayer caller, System.String cmd, System.String[] args) [0x00000] in <filename unknown>:0 
  at Oxide.Core.Libraries.Covalence.CommandHandler.HandleCommand (IPlayer player, System.String command, System.String[] args) [0x00000] in <filename unknown>:0 
  at Oxide.Core.Libraries.Covalence.CommandHandler.HandleChatMessage (IPlayer player, System.String message) [0x00000] in <filename unknown>:0 
  at Oxide.Game.ReignOfKings.Libraries.Covalence.ReignOfKingsCommandSystem.HandleChatMessage (IPlayer player, System.String message) [0x00000] in <filename unknown>:0 
  at Oxide.Game.ReignOfKings.ReignOfKingsCore.IOnServerCommand (UInt64 id, System.String str) [0x00000] in <filename unknown>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0

What about the fix? :c

I haven't had access to do so yet, will do so as soon as I can unless someone else PRs a fix.

Available to test?