Youtube API - 上传视频时出现问题

I'm using google/google-api-php-client version 1.1.6. Then I'm using resumable_upload to upload video to youtube (sample code https://github.com/youtube/api-samples/blob/master/php/resumable_upload.php) And I got this problem when trying to upload new video to youtube with message (view my attached):

'Failed to start the resumable upload (HTTP 500: global, Backend Error)'
Stack trace:
#0 Google_Http_MediaFileUpload->getResumeUri()

Error 500s can happen sometimes with the YouTube API. Did you re-try the request? This is Google's recommended action.