What is it?

Failed to call hook 'OnServerInitialized' on plugin 'SmoothRestarter v3.2.0' (NullReferenceException: )
  at (wrapper managed-to-native) UnityEngine.Component.get_gameObject(UnityEngine.Component)
  at Oxide.Plugins.SmoothRestarter.OnUserConnected (Oxide.Core.Libraries.Covalence.IPlayer user) [0x0000c] in <71fae2d646d6460fa00344d68c6e40e3>:0

  at Oxide.Plugins.SmoothRestarter.OnServerInitialized () [0x00042] in <71fae2d646d6460fa00344d68c6e40e3>:0

  at Oxide.Plugins.SmoothRestarter.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00144] in <71fae2d646d6460fa00344d68c6e40e3>:0

  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <23ba99f131254889867c71f0bd137b1d>:0

  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <157a94ee66ab4a7991faecd1eb84be3b>:0

  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <157a94ee66ab4a7991faecd1eb84be3b>:0