Dropbox & ASP.NET integration

Hi,

I'm using  dropbox.api for c# for downloading files.

in the console project it works perfectly but in the ASP.NET (for now localhost server)

is get stuck in dbx.Files,DownloadAsync Method.

here's the code(very simple):

private async Task _Download(string folder, string file, string destination)
        {
            using (var response = await dbx.Files.DownloadAsync( "/"  + folder + "/" + file))
            {
                using (var fileStream = File.Create(destination))
                {
                    (await response.GetContentAsStreamAsync()).CopyTo(fileStream);
                }               
            }
        }

As i  said, it works in Console Project but not in ASP.NET project