C# I'm getting the following error when playing

I’m trying to run my game and i get the following error:
NullReferenceException: Object reference not set to an instance of an object
JoinGame.RefreshRoomList () (at Assets/Scripts/JoinGame.cs:35)
JoinGame.Start () (at Assets/Scripts/JoinGame.cs:30)

My Code is:

using UnityEngine.UI;
using System.Collections.Generic;
using UnityEngine.Networking;
using UnityEngine.Networking.Match;
using UnityEngine;

public class JoinGame : MonoBehaviour {

	List<GameObject> roomList = new List<GameObject>();

	[SerializeField]
	private Text status;

	[SerializeField]
	private GameObject roomListItemPrefab;

	[SerializeField]
	private Transform roomListParent;

	private NetworkManager networkManager;

	void Start ()
	{
		networkManager = NetworkManager.singleton;
		if (networkManager.matchMaker = null)
		{
			networkManager.StartMatchMaker();
		}

		RefreshRoomList();
	}

	public void RefreshRoomList()
	{
		networkManager.matchMaker.ListMatches(0, 20, "", true, 0, 0, OnMatchList);
		status.text = "Loading...";
	}

	public void OnMatchList(bool success, string extendedInfo, List<MatchInfoSnapshot> matchList)
	{
		status.text = "";
		if (!success || matchList == null)
		{
			status.text = "Couldn't get room list";
			return;
		}

		ClearRoomList();
		foreach (MatchInfoSnapshot match in matchList)
		{
			GameObject _roomListItemGO = Instantiate(roomListItemPrefab);
			_roomListItemGO.transform.SetParent(roomListParent);
			// Have a componetn sit on the gameobject that will take
			// care of setting up the name/amount of users as well
			// as setting up a callback function that will join the game.

			roomList.Add(_roomListItemGO);
		}
	}

	void ClearRoomList()
	{
		for (int i = 0; i < roomList.Count; i++)
		{
			Destroy(roomList*);*
  •  }*
    
  •  roomList.Clear();*
    
  • }*

}

I was missing a = at line 25
:stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue: