function OnFailedToConnect(error: NetworkConnectionError) {
    Debug.Log("Could not connect to server: "+ error);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void OnFailedToConnect(NetworkConnectionError error) {
        Debug.Log("Could not connect to server: " + error);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def OnFailedToConnect(error as NetworkConnectionError):
        Debug.Log(('Could not connect to server: ' + error))