Google URL Shortner cURL返回错误

Question

我有一个API密钥，并尝试使用它来缩短URL。如果我缩短google.com，则会得到缩短的网址

curl https://www.googleapis.com/urlshortener/v1/url?key=MYKEY  -H 'Content-Type: application/json' -d '{"longUrl": "www.google.com"}'

{
 "kind": "urlshortener#url",
 "id": "shorten url",
 "longUrl": "http://www.google.com/"
}

但是，如果我使用yahoo.com之类的其他URL，则会返回错误

curl https://www.googleapis.com/urlshortener/v1/url?key=MYKEY  -H 'Content-Type: application/json' -d '{"longUrl": "www.yahoo.com"}'
{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "forbidden",
    "message": "Forbidden"
   }
  ],
  "code": 403,
  "message": "Forbidden"
 }
}

不确定为什么吗？