I keep getting this error

Failed to call hook 'OnServerInitialized' on plugin 'MoneyTime v2.3.0' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.MoneyTime.InitializePlayer (Oxide.Core.Libraries.Covalence.IPlayer player, System.Single current) [0x00007] in <0d669a47dd9e4d53a9cf674e30dc4da6>:0
  at Oxide.Plugins.MoneyTime.OnServerInitialized () [0x0003a] in <0d669a47dd9e4d53a9cf674e30dc4da6>:0
  at Oxide.Plugins.MoneyTime.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00149] in <0d669a47dd9e4d53a9cf674e30dc4da6>:0
                                                          5kb/s in, 3kb/s out
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <cd9a02fd331347bd82d550bb1a9c8e9f>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <b76ec77c47d1449e92b2baab8603843d>:0