(16:31:56) | Failed to call hook 'CmdChat' on plugin 'BetterChat v5.2.2' (InvalidOperationException: Sequence contains no matching element)
  at System.Linq.Enumerable.First[TSource] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] predicate) [0x00011] in <b7efe7e6e548497fac3c4a6049a0a4b6>:0 
  at Oxide.Plugins.BetterChat.CmdChat (Oxide.Core.Libraries.Covalence.IPlayer player, System.String cmd, System.String[] args) [0x00142] in <89018f9522c5486fa398b444d3af1323>:0 
  at Oxide.Plugins.BetterChat.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x004d5] in <89018f9522c5486fa398b444d3af1323>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <33f7c42a56934dae8ec04b11017dce31>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <33287985591c40d6983f0b8f0e915565>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <33287985591c40d6983f0b8f0e915565>:0

Whenever I typed "chat group add Hacker" in RCON Console this shows up.

It works fine when I'm able to use Chat Command in Game.