Photon Unity. проблема c никами

Всем привет, реализовываю систему ников. При нажатии кнопки create game или search game выходит такая ошибка:

NullReferenceException: Object reference not set to an instance of an object LobbyManager.JoinRoom () (at Assets/Scripts/LobbyManager.cs:38)

код LobbyManager:

using Photon.Pun;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class LobbyManager : MonoBehaviourPunCallbacks
{
    public Text LogText;
    public InputField NicknameInput;

    void Start()
    {
        string nickName = PlayerPrefs.GetString("Nickname", "Player " + Random.Range(1000, 9999));
        PhotonNetwork.NickName = nickName;
        NicknameInput.text = nickName;
        Log("Player's name is set to " + nickName);

        PhotonNetwork.AutomaticallySyncScene = true;
        PhotonNetwork.GameVersion = "1";
        PhotonNetwork.ConnectUsingSettings();
    }

    public override void OnConnectedToMaster()
    {
        Log("Connected to Master");
    }

    public void CreateRoom()
    {
        PhotonNetwork.NickName = NicknameInput.text; // здесь ошибка
        PlayerPrefs.SetString("NickName", NicknameInput.text);
        PhotonNetwork.CreateRoom(null, new Photon.Realtime.RoomOptions { MaxPlayers = 8, CleanupCacheOnLeave = false });
    }

    public void JoinRoom()
    {
        PhotonNetwork.NickName = NicknameInput.text; // и здесь ошибка
        PlayerPrefs.SetString("NickName", NicknameInput.text);
        PhotonNetwork.JoinRandomRoom();
    }

    public override void OnJoinedRoom()
    {
        Log("Joined the room");

        PhotonNetwork.LoadLevel("Game");
    }

    // Update is called once per frame
    private void Log(string message)
    {
        Debug.Log(message);
        LogText.text += "\n";
        LogText.text += message;
    }
}