Help with Pause Menu

I’m trying to get my pause menu to open but it won’t.

I followed this tutorial and it seems to work for him but not for me.

Unity 5 2D Platformer Tutorial - Part 11 - Creating a Pause Menu (part 2) - YouTube

I can’t get the script to appear in the functions when try to assign them in a canvas’ buttons either. I don’t know if that would be why or not.

using UnityEngine;
using System.Collections;

public class PauseMenu : MonoBehaviour {

	public GameObject PauseUI;
	private bool paused = false;


	void Start() 
	{
		PauseUI.SetActive (false);
	}

	void Update() 
	{
		if(Input.GetButtonDown("escape"))
		   {
			paused = !paused;
		   }	

	if(paused) 
	{
	PauseUI.SetActive(true);
	Time.timeScale = 0;
	}

	if(!paused) 
	{
	PauseUI.SetActive(false);
	Time.timeScale =  1;
	}
}

	public void Resume() 
	{
	paused = false;
	}
	
	public void MainMenu() 
	{
	Application.LoadLevel(1);
	}

	public void Quit() 
	{
	Application.Quit();
	}
}

Try if(paused == false) instead of if(!paused), I ran into this problem with my pause screen too, I have ZERO idea why it matters to Unity, but it seemd to somehow register paused == false verse paused not equal to itself… Again, no idea why.