ui Text not responding to collider

Please help I've spent an entire day trying to figure this out and nothing seems to work. I am very new to Unity.

I would like for a text to pop up when I go over a certain area which is marked by a box collider on my terrain and then dissapear after 5 seconds. Everything seems to be working fine in the script as the text is not visible when I begin the game however it is never activated by the box collider. There are no error messages displayed either. I was following this tutorial: (https://www.youtube.com/watch?v=CNNeD9oT4DY)

Here is my script:

 public GameObject uiObject;
 void Start()
 {
     uiObject.SetActive(false);
 }
 //Update is called once per frame
 void OnTriggerEnter(Collider player)
 {
     if (player.gameObject.tag == "Player")
     {
         uiObject.SetActive(true);
         StartCoroutine("WaitForSec");
     }
 }

 IEnumerator WaitForSec()
 {
     yield return new WaitForSeconds(5);
     Destroy(uiObject);
     Destroy(gameObject);
  }

}