youtube-api - ビデオをアップロードしようとすると、Youtube API v3 が 401 を返す

Question

YouTube 用の ServiceAccount アップローダーを使用しています。Youtube API v3 を使用しています。YouTubeにビデオをアップロードする簡単なコンソールアプリケーションがあります

String serviceAccountEmail = "...";

        var certificate = new X509Certificate2(@"G:\Youtube\1ffd6ea22be7c41e0852935a0f35438e4beb2e2d-privatekey.p12", "notasecret", X509KeyStorageFlags.Exportable);
        //, YouTubeService.Scope.YoutubeUpload
        ServiceAccountCredential credential = new ServiceAccountCredential(
           new ServiceAccountCredential.Initializer(serviceAccountEmail)
           {
                                  Scopes = new[] { YouTubeService.Scope.Youtube, YouTubeService.Scope.YoutubeUpload }
           }.FromCertificate(certificate));



        var youtube = new YouTubeService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
        });

        var video = new Video
        {
            Snippet = new VideoSnippet
            {
                Title = "Video title",
                Description = "Video description",
                Tags = new string[] {"tag1", "tag2"},
                CategoryId = "22"
            },
            Status = new VideoStatus {PrivacyStatus = "public"}
        };

        var fileStream = new FileStream("G:\\1.mp4", FileMode.Open);

        var videosInsertRequest = youtube.Videos.Insert(video, "snippet,status", fileStream, "video/*");
        videosInsertRequest.ProgressChanged += videosInsertRequest_ProgressChanged;
        videosInsertRequest.ResponseReceived += videosInsertRequest_ResponseReceived;

        var uploadThread = new Thread(() => videosInsertRequest.Upload());
        uploadThread.Start();
        uploadThread.Join();

        Console.Read();

しかし、このコードはエラーを返します: 応答ステータス コードは成功を示しません: 401 (権限がありません)。 お願い助けて

これは Fiddler による結果です。

    HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer realm="https://www.google.com/accounts/AuthSubRequest", error=invalid_token
Content-Type: application/json
Content-Length: 255
Date: Sun, 10 Nov 2013 14:36:29 GMT
Server: HTTP Upload Server Built on Nov 5 2013 16:15:49 (1383696949)
Alternate-Protocol: 443:quic

{
 "error": {
  "errors": [
   {
    "domain": "youtube.header",
    "reason": "youtubeSignupRequired",
    "message": "Unauthorized",
    "locationType": "header",
    "location": "Authorization"
   }
  ],
  "code": 401,
  "message": "Unauthorized"
 }
}