SetActive() trouble

Hi comm unity )))
I’ve got some problem with UI Panel.
On Panel I got code:
using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class Activate : MonoBehaviour {

	void Awake () {
        gameObject.SetActive(false);
    }
}

It’s disable my PopUp panel on start.

On Button I got code:

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class PopUp : MonoBehaviour {

    GameObject getPopUp;

    public void clickedPopUp()
    {
        getPopUp = GameObject.Find("PopUp");
        getPopUp.SetActive(true);
    }
}

So, Panel disabling perfectly, but when I’m trying to SetActive(true), it’s gives me ERROR : NullReferenceExeption.

I’ll be glad if someone will tell my how to fix it)

So, I kinnda find an option to solve this)

I’ve changed Awake on Start in 1st code, then create Awake in 2nd code and
transfer getPopUp = GameObject.Find(“PopUp”) to Awake, so it can find gameObject before it goes Inactive )))