PU Tutorial error

I have followed the Photon PU Tutorial carefully following each step, but after I declare the bool isConnecting and surround the PhotonNetwork.JoinRandomRoom(); I receive this error everytime I try to start a server using unity this error appears

JoinRandomRoom failed. Client is on MasterServer (must be Master Server for matchmaking) but not ready for operations (State: ConnectingToNameServer). Wait for callback: OnJoinedLobby or OnConnectedToMaster.
UnityEngine.Debug:LogError(Object)
Photon.Pun.PhotonNetwork:JoinRandomRoom(Hashtable, Byte, MatchmakingMode, TypedLobby, String, String[]) (at Assets/Photon/PhotonUnityNetworking/Code/PhotonNetwork.cs:1588)
Photon.Pun.PhotonNetwork:JoinRandomRoom() (at Assets/Photon/PhotonUnityNetworking/Code/PhotonNetwork.cs:1522)
Com.MyCompany.MyGame.Launcher:Connect() (at Assets/Photon/PhotonUnityNetworking/Demos/PunBasics-Tutorial/Scripts/Launcher.cs:93)
UnityEngine.EventSystems.EventSystem:Update() (at C:/Program Files/Unity/Hub/Editor/2019.3.6f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/EventSystem.cs:377)

If someone could help me I would be really grateful

here is my entire launcher c# script(just as the tutorial one):

using UnityEngine;
using Photon.Pun;
using Photon.Realtime;

namespace Com.MyCompany.MyGame
{
    public class Launcher : MonoBehaviourPunCallbacks
    {
        /// <summary>
        /// The maximum number of players per room. When a room is full, it can't be joined by new players, and so new room will be created.
        /// </summary>
        [Tooltip("The maximum number of players per room. When a room is full, it can't be joined by new players, and so new room will be created")]
        [SerializeField]
        private byte maxPlayersPerRoom = 4;


        #region Public Fields

        [Tooltip("The Ui Panel to let the user enter name, connect and play")]
        [SerializeField]
        private GameObject controlPanel;
        [Tooltip("The UI Label to inform the user that the connection is in progress")]
        [SerializeField]
        private GameObject progressLabel;

        #endregion

        #region Private Serializable Fields


        #endregion


        #region Private Fields
        bool isConnecting;

        /// <summary>
        /// This client's version number. Users are separated from each other by gameVersion (which allows you to make breaking changes).
        /// </summary>
        string gameVersion = "1";


        #endregion


        #region MonoBehaviour CallBacks


        /// <summary>
        /// MonoBehaviour method called on GameObject by Unity during early initialization phase.
        /// </summary>
        void Awake()
        {
            // #Critical
            // this makes sure we can use PhotonNetwork.LoadLevel() on the master client and all clients in the same room sync their level automatically
            PhotonNetwork.AutomaticallySyncScene = true;
        }


        /// <summary>
        /// MonoBehaviour method called on GameObject by Unity during initialization phase.
        /// </summary>
        void Start()
        {
            progressLabel.SetActive(false);
            controlPanel.SetActive(true);
           
        }


        #endregion


        #region Public Methods


        /// <summary>
        /// Start the connection process.
        /// - If already connected, we attempt joining a random room
        /// - if not yet connected, Connect this application instance to Photon Cloud Network
        /// </summary>
        public void Connect()
        {
            // keep track of the will to join a room, because when we come back from the game we will get a callback that we are connected, so we need to know what to do then
            isConnecting = PhotonNetwork.ConnectUsingSettings();
            progressLabel.SetActive(true);
            controlPanel.SetActive(false);

            // we check if we are connected or not, we join if we are , else we initiate the connection to the server.
            if (PhotonNetwork.IsConnected)
            {
                // #Critical we need at this point to attempt joining a Random Room. If it fails, we'll get notified in OnJoinRandomFailed() and we'll create one.
                PhotonNetwork.JoinRandomRoom();
            }
            else
            {
                // #Critical, we must first and foremost connect to Photon Online Server.
                PhotonNetwork.ConnectUsingSettings();
                PhotonNetwork.GameVersion = gameVersion;
            }
        }


        #endregion

        #region MonoBehaviourPunCallbacks Callbacks


        public override void OnConnectedToMaster()
        {
            if (isConnecting)
            {
                // #Critical: The first we try to do is to join a potential existing room. If there is, good, else, we'll be called back with OnJoinRandomFailed()
                PhotonNetwork.JoinRandomRoom();
                isConnecting = false;
            }

        }


        public override void OnDisconnected(DisconnectCause cause)
        {
            progressLabel.SetActive(false);
            controlPanel.SetActive(true);
            Debug.LogWarningFormat("PUN Basics Tutorial/Launcher: OnDisconnected() was called by PUN with reason {0}", cause);
        }

        public override void OnJoinRandomFailed(short returnCode, string message)
        {
            Debug.Log("PUN Basics Tutorial/Launcher:OnJoinRandomFailed() was called by PUN. No random room available, so we create one.\nCalling: PhotonNetwork.CreateRoom");

            // #Critical: we failed to join a random room, maybe none exists or they are all full. No worries, we create a new room.
            PhotonNetwork.CreateRoom(null, new RoomOptions { MaxPlayers = maxPlayersPerRoom });
        }

        public override void OnJoinedRoom()
        {
            Debug.Log("PUN Basics Tutorial/Launcher: OnJoinedRoom() called by PUN. Now this client is in a room.");

            if (PhotonNetwork.CurrentRoom.PlayerCount == 1)
            {
                Debug.Log("We load the 'Room for 1' ");


                // #Critical
                // Load the Room Level.
                PhotonNetwork.LoadLevel("Room for 1");
            }


        }
    }
    #endregion

}