why does my loading screen not work for mobile

hi im am making a game and theres a loading screen but it works in the engine but when i finish built the product and i use and emulator to test it it doesnt work

heres my script:
using System.Collections;
using UnityEngine;
using UnityEngine.SceneManagement;
using UnityEngine.UI;

public class leveloader : MonoBehaviour {

public GameObject LoadingScreen;
public Slider Slider;
public Text progressText;

public void LoadLevel (int sceneIndex)


IEnumerator LoadAsynchronously (int sceneIndex)
	AsyncOperation operation = SceneManager.LoadSceneAsync(sceneIndex);


	while (!operation.isDone)
		float progress = Mathf.Clamp01(operation.progress / .9f);

		Slider.value = progress;
		progressText.text = progress * 100f + "%";

		yield return null;


can someone please help me

start your coroutine using string, might solve your problem