can't upload vedio to youtube

See more:

C#

ASP.NET

YouTube

while trying to upload vedio to youtube i got "The remote server returned an error: (403) Forbidden."

please review below my code:

YouTubeRequestSettings settings =
                      new YouTubeRequestSettings(ProjectName, DevKey
                          , GmailEmail, Pwd);

            YouTubeRequest request = new YouTubeRequest(settings);
            Video newVideo = new Video();
            newVideo.Title = "My Test Movie";
            newVideo.Tags.Add(new MediaCategory("Autos", YouTubeNameTable.CategorySchema));

            newVideo.Keywords = "cars, funny";
            newVideo.Description = "My description";
            newVideo.YouTubeEntry.Private = false;
            newVideo.Tags.Add(new MediaCategory("mydevtag, anotherdevtag",
            YouTubeNameTable.DeveloperTagSchema));
            //newVideo.YouTubeEntry.Location = new GeoRssWhere(37, -122);
            // alternatively, you could just specify a descriptive string
            // newVideo.YouTubeEntry.setYouTubeExtension("location", "Mountain View, CA");

            newVideo.YouTubeEntry.MediaSource = new MediaFileSource(flUpload.FileContent, flUpload.FileName, GetFileMime("avi"));

please help