Score Keeper Not Working Fine

[CrazyGamer]

In first loop
When I start the ‘Game’ scene the score is displayed correctly then in ‘Game Over Screen’ scene also it is working fine.

But in second loop
when I click on ‘Play Again’ button then in ‘Game’ scene when I kill an enemy the score is displayed as 0 then in ‘Game Over Screen’ scene it is displayed correctly.

Scripts:-

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ScoreKeeper : MonoBehaviour
{
    int score = 0;

    static ScoreKeeper instance;

    void Awake()
    {
        if(instance != null)
        {
            gameObject.SetActive(false);
            Destroy(gameObject);
        }
        else
        {
            instance = this;
            DontDestroyOnLoad(gameObject);
        }
    }

    public void SetScore(int enemyPoints)
    {
        score += enemyPoints;
    }

    public int GetScore()
    {
        return score;
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using TMPro;
using UnityEngine.UI;

public class UIDisplay : MonoBehaviour
{
    [SerializeField] TextMeshProUGUI scoreText;
    [SerializeField] Slider healthSlider;
    ScoreKeeper scoreKeeper;

    void Awake()
    {
        scoreKeeper = FindObjectOfType<ScoreKeeper>();
    }

    void Update()
    {
        scoreText.text = scoreKeeper.GetScore().ToString("000000000");
    }

    public void SetSliderValue(int healthPoints, int initialHealthPoints)
    {
        healthSlider.value = (float)healthPoints / initialHealthPoints;
    }
}

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using TMPro;

public class GameOverUIDisplay : MonoBehaviour
{
    [SerializeField] TextMeshProUGUI scoreText;
    ScoreKeeper scoreKeeper;

    void Awake()
    {
        scoreKeeper = FindObjectOfType<ScoreKeeper>();
    }

    void Start()
    {
        scoreText.text = scoreKeeper.GetScore().ToString("000000000");
    }
}

[CrazyGamer]

I found the solution.
Problem was with my buttons.
I have prefabed my Game Manager and on click events of buttons I have used that prefab not object of scene.
Maybe this was not loading the ‘Game’ scene correctly which was causing the problems.