chat command doesn't work

Failed to call hook 'cmdChatOpenBox' on plugin 'MysteryBox v1.1.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.MysteryBox.OpenBox (BasePlayer player) [0x0001a] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.MysteryBox.cmdChatOpenBox (BasePlayer player, System.String command, System.String[] args) [0x0003d] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.MysteryBox.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00560] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <112d89ea5d3348c8b949af0ab1a866d2>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <112d89ea5d3348c8b949af0ab1a866d2>:0 

10 hours ago, mcsigu said:

Failed to call hook 'cmdChatOpenBox' on plugin 'MysteryBox v1.1.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.MysteryBox.OpenBox (BasePlayer player) [0x0001a] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.MysteryBox.cmdChatOpenBox (BasePlayer player, System.String command, System.String[] args) [0x0003d] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.MysteryBox.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00560] in <01f15b8d65a74f4fb779aec0fe8f57a0>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <112d89ea5d3348c8b949af0ab1a866d2>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <112d89ea5d3348c8b949af0ab1a866d2>:0 

It can be reproduced? What was the player doin when this happen? Also provide a plugin list.

it happens even on test server without any plugins any time a user writes /mbo

also deleted config file so it's regenerated, and still get the same error, additionally, in server console:

mbr all
Failed to call hook 'ConsoleClearOpenedBoxesCounter' on plugin 'MysteryBox v1.1.2' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.MysteryBox.ClearOpenedBoxesCounter (System.UInt64 userID) [0x000a2] in <c6c05ba813c34fe1b555cd3ed54464b8>:0 
  at Oxide.Plugins.MysteryBox.ConsoleClearOpenedBoxesCounter (ConsoleSystem+Arg args) [0x00098] in <c6c05ba813c34fe1b555cd3ed54464b8>:0 
  at Oxide.Plugins.MysteryBox.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00386] in <c6c05ba813c34fe1b555cd3ed54464b8>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <112d89ea5d3348c8b949af0ab1a866d2>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <112d89ea5d3348c8b949af0ab1a866d2>:0 

... and the one thing I did not delete in testing was the data file. Deleting that solved all issues. 
NOT A PLUGIN ERROR (as 99% of everything, user error) 
Thanks and cheers