When a client connects to server do foreach UNET

Question

How to make when a client connects to server, that my foreach is working. Because when I put the foreach in Update, it's working great. What's the problem?

using UnityEngine;
using UnityEngine.Networking;
using System.Collections;

public class Net : NetworkManager {

    public GameObject[] _mans;

    void Update()
    {
        _mans = GameObject.FindGameObjectsWithTag ("Player");
        Debug.Log (_mans.Length);
    }

    public override void OnClientConnect(NetworkConnection conn)
    {
        foreach (GameObject man in _mans) 
        {
            man.GetComponent<UIManager> ().Play ();
        }
    }

}