(UnityEngine.GameObject target, eventData, +EventFunction`1 functor) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.

( handler, eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:50) UnityEngine.UI.Button.OnPointerClick ( eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:108)

The Scene is added in the build setting too by the way. UnityEngine.UI.Button.Press () (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:66) Scene (-1) couldnt be loaded because it has not been added to the build settings or the AssetBundle has not been loaded. () (at C:/buildslave/unity/build/Runtime/Export/UnityEvent/UnityEvent/UnityEvent_0.cs:58) () (at C:/buildslave/unity/build/Runtime/Export/UnityEvent/UnityEvent.cs:166) LevelManager.NextLevelLoader () (at Assets/Scripts/LevelManager.cs:94) //My Script 'NullReferenceException: Object reference not set to an instance of an object

Scene manager build index unity