Custom Message id

[Hyup98]

i made custom message in client project
Below is the client code.

<NewNetworkManager.cs>
public class CustomGameServerMessageTypes
{
    public const short ReceiveAuthenticate = 900;
    public const short ShutdownMessage = 901;
    public const short MaintenanceMessage = 902;
    public const short HelloMessage = 903;
}
public struct HelloMessage : NetworkMessage
{
    public string data;
    public HelloMessage(string value)
    {
        data = value;
        //Debug.Log($"메시지 생성 완료 : {data},  {this.GetType()}");
    }
}
////////////////////////////////////////////
<Startup.cs>
public class Startup : MonoBehaviour
{
    NewNetworkManager _nm;
    MessageWindow _messageWindow;

    // Use this for initialization
    void Start()
    {
        _nm = NewNetworkManager.Instance;
        _nm.OnDisconnected.AddListener(OnDisconnected);
        _nm.OnConnected.AddListener(OnConnected);
        NetworkClient.RegisterHandler<ShutdownMessage>(OnServerShutdown);
        NetworkClient.RegisterHandler<MaintenanceMessage>(OnMaintenanceMessage);
        //NetworkClient.RegisterHandler<HelloMessage>(HelloMessage); -> here i registe my message
        _messageWindow = MessageWindow.Instance;
        Debug.Log($"네트워크 메니저 인스턴스 아이디: {_nm.GetInstanceID()}");
    }

    private void OnMaintenanceMessage(MaintenanceMessage msg)
    {
        var message = msg;
        _messageWindow.Title.text = "Maintenance Shutdown scheduled";
        _messageWindow.Message.text = string.Format("Maintenance is scheduled for: {0}", message.ScheduledMaintenanceUTC.ToString("MM-DD-YYYY hh:mm:ss"));
        _messageWindow.gameObject.SetActive(true);
    }

    private void OnServerShutdown(ShutdownMessage msg)
    {
        _messageWindow.Title.text = "Shutdown In Progress";
        _messageWindow.Message.text = "Server has issued a shutdown.";
        _messageWindow.gameObject.SetActive(true);
        NetworkClient.Disconnect();
    }


    private void OnConnected() -> Send message here!!
    {
        Debug.Log("connected!@!@!@!@! -> hello message 보내기");
        HelloMessage helloMessage = new HelloMessage("안녕하세요");
        NetworkClient.Send(helloMessage, Channels.Reliable);
        Debug.Log($"메시지 id : {helloMessage.GetType().GetType()}");
    }
    private void OnDisconnected(int? code)
    {
        _messageWindow.Title.text = "Disconnected!";
        _messageWindow.Message.text = "You were disconnected from the server";
        _messageWindow.gameObject.SetActive(true);
    }
}

then i got error in my server how i registe my client message in server(my project based in MpsSamples-main\UnityMirror )
*i registed message in server code already, but it doesn't work
Below is the server code.

<UnityNetworkServer.cs>
public class NewNetworkManager : NetworkManager
{

    public static NewNetworkManager Instance { get; private set; }

    public ConnectedEvent OnConnected = new ConnectedEvent();
    public DisconnectedEvent OnDisconnected = new DisconnectedEvent();

    public class ConnectedEvent : UnityEvent { }
    public class DisconnectedEvent : UnityEvent<int?> { }

    public override void Awake()
    {
        base.Awake();
        Instance = this;
    }

    public override void Start()
    {
        base.Start();
        this.StartClient();
    }


    public override void OnClientConnect()
    {
        base.OnClientConnect();
        Debug.Log("client connected");
        OnConnected.Invoke();
    }


    public override void OnClientDisconnect()
    {
        base.OnClientDisconnect();
        Debug.Log("client disconnected");
        OnDisconnected.Invoke(null);
    }
    public override void OnClientError(Exception ex) { }

    public override void OnClientNotReady() { }

    public override void OnClientChangeScene(string newSceneName, SceneOperation sceneOperation, bool customHandling) { }

    public override void OnClientSceneChanged()
    {
        base.OnClientSceneChanged();
    }
    public override void OnStartClient()
    {
        base.OnStartClient();
    }

    public override void OnStopClient() { }

}


public class CustomGameServerMessageTypes
{
    public const short ReceiveAuthenticate = 900;
    public const short ShutdownMessage = 901;
    public const short MaintenanceMessage = 902;
    public const short HelloMessage = 903;
}

public struct ReceiveAuthenticateMessage : NetworkMessage
{
    public string PlayFabId;
}

public struct ShutdownMessage : NetworkMessage { }

[Serializable]
public struct MaintenanceMessage : NetworkMessage
{
    public DateTime ScheduledMaintenanceUTC;
}

public struct HelloMessage : NetworkMessage
{
    public string data;
    public HelloMessage(string value)
    {
        data = value;
        //Debug.Log($"메시지 생성 완료 : {data},  {this.GetType()}");
    }
}

blow it's my server error

Unknown message id: 14476 for connection: connection(1). This can happen if no handler was registered for this message