Unity выдаёт такую ошибку

NullReferenceException: Object reference not set to an instance of an object
NavMeshPlus.Extensions.Editors.RootSources2dEditor.OnInspectorGUI () (at Assets/NavMeshComponents/Editor/RootSources2dEditor.cs:23)
UnityEditor.UIElements.InspectorElement+<>c__DisplayClass76_0.<CreateInspectorElementUsingIMGUI>b__0 () (at <999cf70008af42ff801367fff45dedb1>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)