public void TryLogin ()
{
    UnityWebRequest req = UnityWebRequest.Get ("Your jenkins login url of network");
    req.method = "GET";
    req.SetRequestHeader("Authorization", "Basic " + Convert.ToBase64String (Encoding.UTF8.GetBytes ("jenkinsId:jenkinsPassword")));

    StartCoroutine (WaitForLoginRequest (req));
}

IEnumerator WaitForLoginRequest(UnityWebRequest req)
{
    yield return req.Send ();

    if (req.isError)
    {
        Debug.Log ("WWW Error: " + req.error);
    }
    else
    {
        Debug.Log("WWW Ok!:");

        string response = Encoding.UTF8.GetString (req.downloadHandler.data);
        Debug.Log ("Response code = " + req.responseCode);
        Debug.Log ("String = " + response);
    }
}