cefsharp DownloadUrlAsync skips Cookie

Question

load url in browser control that require cookie and authentiacaion is ok

  CefSharp.OffScreen.ChromiumWebBrowser browser = new CefSharp.OffScreen.ChromiumWebBrowser(Url, requestContext: reqContext);

but using download url

            var ppp =await browser.GetMainFrame().DownloadUrlAsync(Url);
            var ooop= Encoding.UTF8.GetString(ppp);

redirect to login page and cookie header not sent