GetStreamAsync CopyTo sometimes returns zero bytes [closed]

I have the following routine that downloads a file from a web server. Sometimes the local file is created, but is zero bytes. I am [almost] certain the remote resource exists.

private static void DownloadFile(string strUrl, string strLocalFile)
{
    using (var client = new HttpClient())
    {
        using (var httpClient = new HttpClient())
        {
            using (var streamAsync = httpClient.GetStreamAsync(strUrl))
            {
                using (var fileStream = new FileStream(strLocalFile, FileMode.OpenOrCreate))
                {
                    streamAsync.Result.CopyTo(fileStream);
                }
            }
        }
    }
}