C# CS1503 Hatası?

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


public class server : MonoBehaviourPunCallbacks
{
    // Start is called before the first frame update
    void Start()
    {
        PhotonNetwork.ConnectUsingSettings();   
    }
    public override void OnConnectedToMaster()
    {
        base.OnConnectedToMaster();
        Debug.Log("connected server");
        PhotonNetwork.JoinLobby();
    }
    public override void OnJoinedLobby()
    {
        base.OnJoinedLobby();
        Debug.Log("connect lobby");

        PhotonNetwork.JoinRandomOrCreateRoom("oda", new RoomOptions { MaxPlayers=2, IsOpen=true, IsVisible=true }, TypedLobby.Default);
        
    }
    void Update()
    {
        
    }
}