Call JoinRandomRoom, but both OnJoinedRoom and OnJoinRandomFailed not called

Here is my code and debug log message, please help me thank you
public override void OnConnectedToMaster()
            Debug.Log("LauncherPhoton: OnConnectedToMaster() was called by PUN");

        public override void OnJoinedRoom()
            Debug.Log("LauncherPhoton: OnJoinedRoom() called by PUN. Now this client is in a room.");

        public override void OnJoinRandomFailed(short returnCode, string message)
            Debug.Log("LauncherPhotonr:OnJoinRandomFailed() was called by PUN. No random room available, so we create one.\nCalling: PhotonNetwork.CreateRoom");
            PhotonNetwork.CreateRoom(null, new RoomOptions { MaxPlayers = maxPlayersPerRoom});

LauncherPhoton: OnConnectedToMaster() was called by PUN

Debug log message stop right here, nothing callback happen when call PhotonNetwork.JoinRandomRoom()