Can't access other game object in build-ed version of the game but when testing in editor it works alright

So I have start button with code:

GameControlScr gameControlScr;
	void Start () {
		gameControlScr = GameObject.Find ("GameControl").GetComponent<GameControlScr>();
	void OnMouseDown()

When I test it from unity editor it works fine. It calls testMethod() and new scene is loaded. But when I build project into android or pc versions it won’t call this method. It seems like it can’t access gameControlScr. I also tried making gameControlSrc a static reference and it won’t work as well. Btw testMethod() just have this line of code:

public void testMethod(){

Make sure you have added all your scenes to the build. You can do this by either going into the “Build Settings” and clicking on “Add Current” to add the current scene or by draging and droping your scenes into the Build Settings. For further information look here