Cannot Change Emission Value

Unity Engine
1

Hey! Can anyone fix my issue? My emission value doesn’t change, but all the tutorials I’ve watched tell you to write “material.Disable(”_EMISSION");" and yes I have a variable for the material. I want my material emission to flicker when I am reloading. Any answers?

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

public class EmisionControl : MonoBehaviour
{

    public Material emitValue;
    public GunScript gunScript;
    // Start is called before the first frame update
    void Start()
    {
        emitValue.EnableKeyword("_EMISSION");
    }

    // Update is called once per frame
    void Update()
    {
        if (gunScript.isReloading)
        {
            StartCoroutine(Flicker());
        }
    }

    IEnumerator Flicker()
    {
        emitValue.DisableKeyword("_EMISSION");
        yield return new WaitForSeconds(1f);
        emitValue.EnableKeyword("_EMISSION");
        yield return new WaitForSeconds(.6f);
        emitValue.DisableKeyword("_EMISSION");
        yield return new WaitForSeconds(.4f);
        emitValue.EnableKeyword("_EMISSION");
        yield return new WaitForSeconds(.4f);
        emitValue.DisableKeyword("_EMISSION");
        yield return new WaitForSeconds(.6f);
        emitValue.EnableKeyword("_EMISSION");
    }
}
2

Also, I get the console error “Object reference not set to an instance of an object”