我使用YouTube API更新YouTube上的视频，问题是我想更新视频Publishat状态时从YouTube上得到了这个错误。

[2017-11-29 12:19:39] local.ERROR: Google_Service_Exception: {
 "error": {
  "errors": [
   {
    "domain": "youtube.video",
    "reason": "invalidVideoMetadata",
    "message": "The request metadata is invalid.",
    "locationType": "other",
    "location": "body"
   }
  ],
  "code": 400,
  "message": "The request metadata is invalid."
 }
}

但奇怪的是，只有当我设置了publishAt值（我已经将privacyStatus更新为'private'）时，我才会得到这个错误。

$params     = array();
$part       = 'snippet,contentDetails,player,status'; 

$properties = [
    'snippet.categoryId'            => $this->video->youtube_category_id,
    'snippet.defaultLanguage'       => '',
    'snippet.description'           => $this->video->video_description,
    'snippet.tags[]'                => !empty($this->video->tags->pluck('tag_value')->toArray())?implode(',',$this->video->tags->pluck('tag_value')->toArray()):'',
    'snippet.title'                 => $this->video->video_title,
    'status.embeddable'             => true,
    'status.license'                => '',
    'status.privacyStatus'          => !empty($this->video->privacy_status) ? $this->video->privacy_status : 'private',
    'status.publishAt'		    => empty($this->video->video_release_date) ? "" : date('Y-m-d\TH:i:s.sP',strtotime($this->video->video_release_date)),
    'status.publicStatsViewable'    => ''
];

if(!empty($this->video->youtube_id)){
  $properties['id'] = $this->video->youtube_id;
}

$service    = new \Google_Service_YouTube($client);
$propertyObject = $this->createResource($properties);
$resource = new \Google_Service_YouTube_Video($propertyObject);

if($this->upload) $client->setDefer(true);

if(!empty($this->video->youtube_id))
{
  $request = $service->videos->update($part, $resource, $params);
}
elseif($this->upload) 
{
  $request = $service->videos->insert($part, $resource, $params);
}
else
{
   exit;
}

我在网上搜索了这个问题，但没有找到任何解决方案。请帮助，谢谢。
注：使用此代码，上传视频成功。