NetworkServer.connections returns null?

When I try to access the NetworkServer.connections variable when the player count is >0 (1 client), the NetworkServer.connections variable returns null (even though the server is online). Does anyone know why?

Here is my code:

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

public class Menu : MonoBehaviour
{

	void OnGUI()
	{
		if(!NetManager.Get.isConnected)
		{
			if(GUILayout.Button("Start Server"))
			{
				NetManager.Get.StartServer();
			}
			if(GUILayout.Button("Connect"))
			{
				NetManager.Get.ConnectToServer();
			}
		}
		else
		{
			GUILayout.Label("Is " + ((NetManager.Get.isClient) ? "client" : "server"));
			if(GUILayout.Button("Disconnect"))
			{
				NetManager.Get.Disconnect();
			}
			if(NetManager.Get.isServer)
			{
				GUILayout.Label("Connections: " + NetworkServer.connections.Count);
				foreach(NetworkConnection con in NetworkServer.connections)
				{
					GUILayout.Label("Connection " + con.connectionId + ", address: " + con.address);
				}
			}
			if(NetManager.Get.isClient)
			{
				GUILayout.Label("Connections: " + NetworkClient.allClients.Count);
				foreach(NetworkClient client in NetworkClient.allClients)
				{
					GUILayout.Label("Connection " + client.connection.connectionId + ", address: " + client.connection.address);
				}
			}
		}
	}

}

Replace:

GUILayout.Label("Connection " + con.connectionId + ", address: " + con.address);

by that

GUILayout.Label(con);

Or use

  if (con == null)