Instantiate is ending function immediately

Hi, im working on simple app where player can pass some info via WebSockets.
I want to create object when player connect, but function just end on Instantiate, without any error!
Without Instantiate everything works just fine.

Service code:

public class GreetingService : WebSocketBehavior
{
    protected override void OnMessage(MessageEventArgs e)
    {
        GreetingMessage data = JsonUtility.FromJson<GreetingMessage>(e.Data);
        PointManager.Instance.PlayerConnected(data);
    }
}
[System.Serializable]
public class GreetingMessage
{
    public uint id;
}

Working function:

public static PointManager Instance;
    [SerializeField] Camera mainCamera;
    [NonReorderable][SerializeField] private List<Player> players = new List<Player>();
    [SerializeField] private GameObject pointerPrefab;
    [SerializeField] private Transform screen;
    [SerializeField] private Transform hitMarker;

public void PlayerConnected(GreetingMessage message)
    {
        Debug.Log("Start function");

        //Instantiate(pointerPrefab, Vector3.zero, Quaternion.identity);

        Debug.Log("End function");
    }


And now its broken:

public void PlayerConnected(GreetingMessage message)
    {
        Debug.Log("Start function");

        Instantiate(pointerPrefab, Vector3.zero, Quaternion.identity);

        Debug.Log("End function");
    }

Looks like WebSocketSharp wasn’t that grat idea as I assumed:
https://forum.unity.com/threads/websocket-sharp-unity-server.1031890/