找不到Facebook对象

通过Facebook Graph API,可以通过以下get请求获取事件的封面图像:

https://graph.facebook.com/169768270447838?fields=cover&access_token=<ACCESS_TOKES>

适用于以下事件id(UrL: https://www.facebook.com/events/925315510978238/ ):

925315510978238

但对于另一个事件id,它不再起作用( https://www.facebook.com/events/169768270447838/ ):

169768270447838

{
"error": {
    "message": "Unsupported get request. Object with ID '169768270447838' does not exist, cannot be loaded due to missing permissions, or does not support this operation. Please read the Graph API documentation at https://developers.facebook.com/docs/graph-api",
    "type": "GraphMethodException",
    "code": 100,
    "error_subcode": 33,
    "fbtrace_id": "CnDEBaBv1HG"
}

}

几天前它成功了,我不知道为什么它不再有效了。