Help to play music whenever the character enters a GameObject...

I'm making a simple project where whenever my 3D character enters in a GameObject a music starts to play in eternal Loop and when the character leave out the GameObject the song stops playing, and when he enter into the GameObject again the music plays again from the beginning.

But I'm just getting to make it once (then when my character comes back into the GameObject no longer plays any music... this is like if the GameObject had been destroyed after he leaves the GameObject).

Please, I need your help to fix it.

 using UnityEngine;
 using System.Collections;
 
 public class PlaySound : MonoBehaviour
 {   
     AudioSource audio;
   
     void Start()
     {
         audio = GetComponent<AudioSource>();
     }
 
     void OnTriggerEnter(Collider other)
     {
         if (other.gameObject.tag == "Player")
         {
           
             GetComponent<AudioSource>().Play();
             audio.loop = true;
         }
     }
 
     void OnTriggerExit(Collider other)
     {
         if (other.gameObject.tag == "Player")
         {
             GetComponent<AudioSource>().Stop();
             audio.loop = false;
         }
     }
 
 }