Getting this error when players connect and then are disconnected:

Failed to call hook 'OnPlayerDisconnected' on plugin 'Authentication v2.1.2' (ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index)
  at System.ThrowHelper.ThrowArgumentOutOfRangeException (System.ExceptionArgument argument, System.ExceptionResource resource) [0x00029] in <fb001e01371b4adca20013e0ac763896>:0
  at System.ThrowHelper.ThrowArgumentOutOfRangeException () [0x00000] in <fb001e01371b4adca20013e0ac763896>:0
  at System.Collections.Generic.List`1[T].RemoveAt (System.Int32 index) [0x00009] in <fb001e01371b4adca20013e0ac763896>:0
  at Oxide.Plugins.Authentication.OnPlayerDisconnected (BasePlayer player) [0x00034] in <92c605573cb14c7daa2a7431d113df32>:0
  at Oxide.Plugins.Authentication.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x0033c] in <92c605573cb14c7daa2a7431d113df32>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <09575a60985045248bcb43b20faeeb99>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <bae5f1223fce49c493b01571c99dce02>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <bae5f1223fce49c493b01571c99dce02>:0