title: Upload a video to google using GTLRYouTubeService fails
body: <p>I'm trying to upload a video to youtube using <code>GTLRYouTubeService</code> from my iOS-app</p>
  
  <p>The login process is done via <code>GIDSignIn</code> and works so far.</p>
  
  <p>When the user logged in, I'm setting up the youtube-service:</p>
  
  <pre><code>self.youTubeService = [GTLRYouTubeService new];
  self.youTubeService.APIKey = API_KEY;
  self.youTubeService.authorizer = user.authentication.fetcherAuthorizer;
  </code></pre>
  
  <p>Then I'm preparing the video object like this:</p>
  
  <pre><code>GTLRYouTube_VideoStatus *status = [GTLRYouTube_VideoStatus object];
  status.privacyStatus = @"private";
  
  GTLRYouTube_VideoSnippet *snippet = [GTLRYouTube_VideoSnippet object];
  snippet.title = self.mTitleField;
  snippet.descriptionProperty = self.mDescriptionField;
  snippet.tags = [self.mKeywordsField componentsSeparatedByString:@","];
  
  GTLRYouTube_Video *video = [GTLRYouTube_Video object];
  video.status = status;
  video.snippet = snippet;
  </code></pre>
  
  <p>After that, I initialize the upload:</p>
  
  <pre><code>GTLRUploadParameters *uploadParameters =
      [GTLRUploadParameters uploadParametersWithFileURL:fileToUploadURL
                                               MIMEType:@"video/mp4"];
      uploadParameters.uploadLocationURL = locationURL;
  
      GTLRYouTubeQuery_VideosInsert *query =
      [GTLRYouTubeQuery_VideosInsert queryWithObject:video
                                                part:@"snippet,status"
                                    uploadParameters:uploadParameters];
  
      [self.mProgressView setProgress: 0.0];
  
      query.executionParameters.uploadProgressBlock = ^(GTLRServiceTicket *ticket,
                                                        unsigned long long numberOfBytesRead,
                                                        unsigned long long dataLength) {
          NSLog(@"Bytes read %f", (double)numberOfBytesRead);
          [self.mProgressView setProgress: (1.0 / (double)dataLength) * (double)numberOfBytesRead];
      };
  
      NSLog(@"YT-Service %@", self.youTubeService.authorizer); // Returns not null
  
      _uploadFileTicket = [self.youTubeService executeQuery:query
                              completionHandler:^(GTLRServiceTicket *callbackTicket,
                                                  GTLRYouTube_Video *uploadedVideo,
                                                  NSError *callbackError) {
                                  // Callback
                                  _uploadFileTicket = nil;
                                  if (callbackError == nil) {
  
                                      UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Uploaded" message:@"Your video has been uploaded to YouTube" preferredStyle:UIAlertControllerStyleAlert];
                                      UIAlertAction *okButton = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
                                      [alert addAction:okButton];
                                      [self presentViewController:alert animated:YES completion:nil];
  
                                  } else {
  
                                      UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Upload failed" message:[NSString stringWithFormat:@"%@", callbackError.localizedDescription] preferredStyle:UIAlertControllerStyleAlert];
                                      UIAlertAction *okButton = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
                                      [alert addAction:okButton];
                                      [self presentViewController:alert animated:YES completion:nil];
  
                                  }
  
                                  self.isUploading = NO;
                                  [self.mProgressView setProgress: 0.0];
  
                              }];
  </code></pre>
  
  <p>But the service returns a 403 (Access denied) error.</p>
  
  <p>Any ideas what's going on here?</p>
  
  <p>[EDIT]</p>
  
  <p>After further investigation, I saw that the service returns «insufficient permissions» - but my account is set up correctly. Uploading videos via YouTube page works.</p>