Facebook 访问令牌调试器说我的访问令牌是有效的：
Issued 1368430222 (24 minutes ago)
Expires 1373614222 (in about 2 months)
Valid True
但是当我在 Graph API Explorer 中对其进行测试时，它会因以下错误而失败：
{
"error": {
"message": "An active access token must be used to query information about the current user.",
"type": "OAuthException",
"code": 2500
}
}