I am getting this error, also when build on phone everything works just camera is black
NullReferenceException: Object reference not set to an instance of an object
easyar.ImageTracker.unloadTarget (easyar.Target target, easyar.CallbackScheduler callbackScheduler, System.Action`2[T1,T2] callback) (at Assets/EasyAR/Scripts/csapi.cs:4683)
easyar.ImageTrackerBehaviour.UnloadImageTarget (ImageTargetController controller, System.Action`2[T1,T2] callback) (at Assets/EasyAR/Scripts/ImageTrackerBehaviour.cs:201)
ImageTargetController.OnDestroy () (at Assets/EasyAR/Scripts/ImageTargetController.cs:265)