Activating Objects with collision of another objects

Hi experts, I'm giving my first steps with Unity and doing my first tutorial, Roll a Ball tutorial.

After doing it completely I was trying to add something, I want to set to active every object that I deactivated by picking up the collectables when the ball hits the walls

I added this code to the ball (player) Script trying to do so but does not work:

     private GameObject[] pickups = new GameObject[12];
 
     void OnCollisionEnter(Collision col){
         if (col.gameObject.CompareTag ("Wall")) {
             pickups = GameObject.FindGameObjectsWithTag("Pick Up");
             foreach(GameObject go in pickups){
                 go.SetActive(true);
             }
         }

Hope that someone can help me with this,

Best Jose