C#Youtube api V3-值不能为null错误异常

我正在使用C#Youtube客户端API v3将字幕上传到我的视频中。上传视频效果很好（所以我认为在身份验证和凭证方面没有问题）。我尝试过类似问题中推荐的各种可能的选择，但没有一个对我有效

我的工作范围如下：

YouTubeService.Scope.Youtube, YouTubeService.Scope.YoutubeForceSsl, YouTubeService.Scope.Youtubepartner

        string zFile = @"subs.srt";

        using (var fileStream = new FileStream(zFile, FileMode.Open))
        {

            Caption cap = new Caption();
            cap.Snippet = new CaptionSnippet();
            cap.Snippet.VideoId = "_VIDEO_ID";
            cap.Snippet.Language = "en";
            cap.Snippet.Name = "Test";
            cap.Snippet.IsDraft = false;
            const int KB = 0x400;
            var minimumChunkSize = 256 * KB;


            CaptionsResource.InsertMediaUpload req = youtubeService.Captions.Insert(cap, "snippet" , fileStream, "*/*");
            req.Sync = true;
            req.ProgressChanged += videosInsertRequest_ProgressChanged;
            req.ChunkSize = minimumChunkSize * 8;
            //req.ResponseReceived += videosInsertRequest_ResponseReceived;

            IUploadProgress result = req.Upload();
        }

System.ArgumentNullException: Value cannot be null.
Parameter name: baseUri

编辑：（根据一条注释中的要求，在下面添加了与服务初始化相关的代码）

代码的其他重要部分如下所示：

YouTubeService.Scope.Youtube, YouTubeService.Scope.YoutubeForceSsl, YouTubeService.Scope.Youtubepartner

        string zFile = @"subs.srt";

        using (var fileStream = new FileStream(zFile, FileMode.Open))
        {

            Caption cap = new Caption();
            cap.Snippet = new CaptionSnippet();
            cap.Snippet.VideoId = "_VIDEO_ID";
            cap.Snippet.Language = "en";
            cap.Snippet.Name = "Test";
            cap.Snippet.IsDraft = false;
            const int KB = 0x400;
            var minimumChunkSize = 256 * KB;


            CaptionsResource.InsertMediaUpload req = youtubeService.Captions.Insert(cap, "snippet" , fileStream, "*/*");
            req.Sync = true;
            req.ProgressChanged += videosInsertRequest_ProgressChanged;
            req.ChunkSize = minimumChunkSize * 8;
            //req.ResponseReceived += videosInsertRequest_ResponseReceived;

            IUploadProgress result = req.Upload();
        }

System.ArgumentNullException: Value cannot be null.
Parameter name: baseUri

执行上述代码时得到的异常如下：

YouTubeService.Scope.Youtube, YouTubeService.Scope.YoutubeForceSsl, YouTubeService.Scope.Youtubepartner

        string zFile = @"subs.srt";

        using (var fileStream = new FileStream(zFile, FileMode.Open))
        {

            Caption cap = new Caption();
            cap.Snippet = new CaptionSnippet();
            cap.Snippet.VideoId = "_VIDEO_ID";
            cap.Snippet.Language = "en";
            cap.Snippet.Name = "Test";
            cap.Snippet.IsDraft = false;
            const int KB = 0x400;
            var minimumChunkSize = 256 * KB;


            CaptionsResource.InsertMediaUpload req = youtubeService.Captions.Insert(cap, "snippet" , fileStream, "*/*");
            req.Sync = true;
            req.ProgressChanged += videosInsertRequest_ProgressChanged;
            req.ChunkSize = minimumChunkSize * 8;
            //req.ResponseReceived += videosInsertRequest_ResponseReceived;

            IUploadProgress result = req.Upload();
        }

System.ArgumentNullException: Value cannot be null.
Parameter name: baseUri

请注意，我已经尝试了

代码段，状态也不可用

感谢社区的支持。
我想你需要检查一下

CaptionsResource.InsertMediaUpload req = youtubeService.Captions.Insert(cap, "snippet" , fileStream, "*/*");

看看这个帖子：
你在哪里初始化YouTube服务？你能给出代码吗？只是在编辑部分添加了与YouTube服务初始化相关的代码。事实上，我以前看过那个线程，甚至在那个线程中，他最终也出现了与我相同的错误，这没有帮助。我还提到，我尝试了“snippet”和“snippet，status”，但在这两种情况下都会出现相同的错误。