C# 远程服务器返回错误：（403）禁止。。在谷歌短网址

我试图通过传递原始url字符串来创建短url，但它给出了一个异常

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您在My_API_key中放了什么键？服务器密钥？哪个域名？删除上面的评论！我问的是哪种密钥类型和哪个域-不写您的密钥403表示禁止，所以请检查您的凭据和设置信息-您是否在google开发者控制台中对密钥的使用（例如http引用器、ip地址）进行了任何限制？如果是这样，请检查您是否遵守了这些规定。我没有设置任何限制@Adyson我们如何知道密钥类型和域@KobyDouek

 public string GetShortURL(string longUrl)
    {

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.googleapis.com/urlshortener/v1/url?key=My_API_Key");
        request.Method = "POST";           
        request.ContentType = "application/json";
        string requestData = string.Format(@"{{""longUrl"": ""{0}""}}", longUrl);
        byte[] requestRawData = Encoding.ASCII.GetBytes(requestData);
        request.ContentLength = requestRawData.Length;
        Stream requestStream = request.GetRequestStream();
        requestStream.Write(requestRawData, 0, requestRawData.Length);
        requestStream.Close();

        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        StreamReader responseReader = new StreamReader(response.GetResponseStream());
        string responseData = responseReader.ReadToEnd();
        responseReader.Close();

        return responseData;
    }