The functionality of the plugin has been disrupted

[MonumentOwner] The functionality of the plugin has been disrupted. There is no critical malfunction, but please report this message to the developer!
[MonumentOwner] The functionality of the plugin has been disrupted. There is no critical malfunction, but please report this message to the developer!
[MonumentOwner] The functionality of the plugin has been disrupted. There is no critical malfunction, but please report this message to the developer!
[MonumentOwner] The functionality of the plugin has been disrupted. There is no critical malfunction, but please report this message to the developer!
[MonumentOwner] The functionality of the plugin has been disrupted. There is no critical malfunction, but please report this message to the developer!
NullReferenceException: Object reference not set to an instance of an object
  at Oxide.Plugins.MonumentOwnerExtensionMethods.ExtensionMethods.FirstOrDefault[TSource] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] predicate) [0x00000] in <b2552804d4464b85980d0eacddeb1ac2>:0 
  at Oxide.Plugins.MonumentOwner.CanTimeOwner (System.String MonumentID, System.UInt64 steamId, System.Double cooldown) [0x00013] in <b2552804d4464b85980d0eacddeb1ac2>:0 
  at Oxide.Plugins.MonumentOwner+ControllerMonument.IfPlayerCantBeOwner (BasePlayer player) [0x0001c] in <b2552804d4464b85980d0eacddeb1ac2>:0 
  at Oxide.Plugins.MonumentOwner+ControllerMonument.TimerForGetOwner () [0x000be] in <b2552804d4464b85980d0eacddeb1ac2>:0 
  at InvokeHandlerBase`1[T].DoTick () [0x00109] in <fd076a8a8d76445cb1509f0330ba8152>:0 
  at InvokeHandlerBase`1[T].LateUpdate () [0x0000c] in <fd076a8a8d76445cb1509f0330ba8152>:0 

Changed Status from Pending to Work in Progress

Thank you for your message. Please tell me if you have any ideas why this happened? As a result of what situation?

I've not see any other errors around when this popped up so im unsure