WebClient.DownloadData() returns 404 with .axd

Question

I'm trying to download a .axd picture link, but I'm getting not found error(404). In local server, works fine, but I get 404 on production Server. Is there anything I must to set up in web.config or something?

    public System.Drawing.Image DownloadImage(string url)
    {
        using (var webClient = new WebClient())
        {
            byte[] fileBytes;
            try
            { 
            fileBytes= webClient.DownloadData(url);
            }
            catch (WebException ex)
            {
               // (HttpWebResponse)ex.Response).StatusCode
                Util.GerarLog("DownloadImage", ex.Message + " " + ex.InnerException + "URL: " + url + "Response: " + ((HttpWebResponse)ex.Response).StatusCode.ToString(), "Image");
                throw new Exception(ex.Message + " " + ex.InnerException);
            }
           return ByteArrayToImage(fileBytes);
        }
    }

    public static System.Drawing.Image ByteArrayToImage(byte[] fileBytes)
    {
        using (var stream = new MemoryStream(fileBytes))
        {
            return System.Drawing.Image.FromStream(stream);
        }
    }