Im getting a "NullReferenceException: Object reference not set to an instance of an object" error not sure why.

I'm following quill18creates's tutorial on making a Multiplayer FPS and I'm on part 5 of his tutorial.

I get this error:

NullReferenceException: Object reference not set to an instance of an object NetworkManager.SpawnMyPlayer () (at Assets/NetworkManager.cs:45) NetworkManager.OnJoinedRoom () (at Assets/NetworkManager.cs:36) UnityEngine.GameObject:SendMessage(String, Object, SendMessageOptions) NetworkingPeer:SendMonoMessage(PhotonNetworkingMessage, Object[]) (at Assets/_Imported/Photon Unity Networking/Plugins/PhotonNetwork/NetworkingPeer.cs:1955) NetworkingPeer:OnEvent(EventData) (at Assets/_Imported/Photon Unity Networking/Plugins/PhotonNetwork/NetworkingPeer.cs:1791) ExitGames.Client.Photon.PeerBase:DeserializeMessageAndCallback(Byte[]) ExitGames.Client.Photon.EnetPeer:DispatchIncomingCommands() ExitGames.Client.Photon.PhotonPeer:DispatchIncomingCommands() PhotonHandler:Update() (at Assets/_Imported/Photon Unity Networking/Plugins/PhotonNetwork/PhotonHandler.cs:83)

And this is my code:

 using UnityEngine;
 using System.Collections;
 
 public class NetworkManager : MonoBehaviour {
     
     public Camera standbyCamera;
     SpawnSpot[] spawnSpots;
 
     // Use this for initialization
     void Start () {
         spawnSpots = GameObject.FindObjectsOfType<SpawnSpot> ();
         Connect ();
     }
     
     void Connect () {
         PhotonNetwork.ConnectUsingSettings ("v1.0.0");
     }
 
     void OnGUI() {
         GUILayout.Label (PhotonNetwork.connectionStateDetailed.ToString() );
     }
 
     void OnJoinedLobby() {
         Debug.Log ("Joined Lobby");
         PhotonNetwork.JoinRandomRoom ();
     }
 
     void OnPhotonRandomJoinFailed() {
         Debug.Log ("Failed To Join Room");
         PhotonNetwork.CreateRoom (null);
     }
 
     void OnJoinedRoom() {
         Debug.Log ("Joined Room");
 
         SpawnMyPlayer ();
     }
 
     void SpawnMyPlayer() {
         SpawnSpot mySpawnSpot = spawnSpots [Random.Range (0, spawnSpots.Length)];
         GameObject myPlayerGO = (GameObject)PhotonNetwork.Instantiate ("PlayerController", mySpawnSpot.transform.position, mySpawnSpot.transform.rotation, 0);
         standbyCamera.enabled = false;
 
         ((MonoBehaviour)myPlayerGO.GetComponent("FPSInputController")).enabled = true;
         ((MonoBehaviour)myPlayerGO.GetComponent("MouseLook")).enabled = true;
         myPlayerGO.transform.FindChild("Main Camera").gameObject.SetActive(true);
     }
 }
 

Not sure where im going wrong, it's my first time using C#.