Failed to call hook 'OnPlayerSleepEnded' on plugin 'TheButton v1.0.8' (NullReferenceException: Object reference not set to an instance of an object)

(14:59:26) | Failed to call hook 'OnPlayerSleepEnded' on plugin 'TheButton v1.0.8' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.TheButton.OnPlayerSleepEnded (BasePlayer player) [0x00024] in <7064ffc294ac4d0ea0f78fee736963d7>:0 
  at Oxide.Plugins.TheButton.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00194] in <7064ffc294ac4d0ea0f78fee736963d7>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <87ce9ac9776a48658bc55eae6debe38b>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <18d4f19bbc844191b11ed9e69284d09b>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <18d4f19bbc844191b11ed9e69284d09b>:0

I run a carbon server on a dedicated machine. I am getting the same error.

Failed to call internal hook 'OnPlayerSleepEnded' on plugin 'TheButton v1.0.8' [3025469128] (Object reference not set to an instance of an object.)
   at void Oxide.Plugins.TheButton.OnPlayerSleepEnded(BasePlayer player) in /home/container/carbon/plugins/TheButton.cs:line 110
   at object Oxide.Plugins.TheButton.InternalCallHook(uint hook, object[] args) in TheButton.cs/Internal:line 98