Health bar sync with the health code script

I create an UI image with the health bar and a script for it, but when my player is attacked, the image of the health bar don't change, just in the inspector the health shows the damage change. How can I make the UI image health bar to change when player is attacked? Do I need to change something in the script? using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI; using UnityEngine.SceneManagement;

 public class HealthBar : MonoBehaviour
 {
     public static HealthBar singleton;
     public Image currentHealthbar;
     public Text ratioText;
 
     public float currentHealth;
     public float maxHealth = 100f;
     public bool isDead = false;
     public bool isGameOver = false;
     public GameObject gameOverText;
 
 
     private void Awake()
     {
         singleton = this;
     }
 
     // Start is called before the first frame update
     private void Start()
     {
         currentHealth = maxHealth;
         UpdateHealthbar();
     }
 
     // Update is called once per frame
     private void UpdateHealthbar()
     {
         float ratio = currentHealth/ maxHealth;
         currentHealthbar.rectTransform.localScale = new Vector3(ratio, 1, 1);
         ratioText.text = (ratio * 100).ToString("0") + '%' ;
     }
 
     void Update()
     {
         if(currentHealth < 0)
         {
             currentHealth = 0;
         }
     }
 
     public void DamagePlayer(float damage)
     {
         if(currentHealth > 0)
         {
             currentHealth -= damage;
         }
         else
         {
             Dead();
 
             if (isGameOver && Input.GetMouseButtonDown(0))
             {
                 SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
 
             }
         }
 
         UpdateHealthbar();
     }
 
     void Dead()
     {
         currentHealth = 0;
         isDead = true;
         Debug.Log("Player is dead");
 
         gameOverText.SetActive(true);
         isGameOver = true;
     }
 }