AudioSource, UnassignedReferenceException?

Unity Engine
,
1

I wrote a script to lower the volume music and then load a scene but I get an UnassignedReferenceException (The Audio Source is on another Game Object).

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

public class StartGame : MonoBehaviour {

    public AudioSource music;

    bool loadGame = false;

    public void Update(){
        if (loadGame)
            music.volume = Mathf.Lerp (music.volume, 0, Time.deltaTime * 3);
       
        if (music.volume <= 0.01f)
            SceneManager.LoadScene (1);
    }

    public void LoadGame(){
        loadGame = true;
    }
}

Am I doing something wrong? The script works exactly as intended.

2

Nevermind I already solved it. It turns out the script was also added in another Game Object without the Audio Source, that was the one trowing the exception.