PHP cURL 问题..错误 401

>我把一个功能从工作 C# 类移植到 PHP 类我正在尝试做一个非常简单的任务，但性能不同，我找不到问题，也许你们可以提供帮助。

这是 C# 代码（不是我的，按原样工作，敏感数据隐藏）：

        Stream requestStream = null;
        HttpWebRequest webRequest = null;
        StringBuilder postBuilder = null;
        HttpWebResponse webResponse = null;
        string requestUrl = null;
        string cookieString = null;
        byte[] rawPostData = null;
        requestUrl = "https://some_server/Login";
        webRequest = (HttpWebRequest)HttpWebRequest.Create(requestUrl);
        postBuilder = new StringBuilder();
        postBuilder.Append("<?xml version='"1.0'" ?>");
        postBuilder.Append("<authorization>");
        postBuilder.Append("<username><![CDATA[some_name]]></username>");
        postBuilder.Append("<password><![CDATA[some_password]]></password>");
        postBuilder.Append("<domain><![CDATA[some_domain]]></domain>");
        postBuilder.Append("</authorization>");
        rawPostData = Encoding.Default.GetBytes(postBuilder.ToString());
        webRequest.ContentType = "text/xml";
        webRequest.Accept = "*/*,text/xml";
        webRequest.ContentLength = rawPostData.Length;
        webRequest.Method = "POST";
        webRequest.UserAgent = "dsaxess/special";
        requestStream = webRequest.GetRequestStream();
        requestStream.Write(rawPostData, 0, rawPostData.Length);
        requestStream.Flush();

        webResponse = (HttpWebResponse)webRequest.GetResponse();
        Debug.WriteLine("Status: " + webResponse.StatusCode);
        //Debug.Write(webRequest.Headers);
        //Debug.Write(webResponse.Headers);
        requestStream.Close();
        requestStream = null;
        postBuilder = null;
        Debug.WriteLine("Done!");

这是我的PHP代码：

    $ch = curl_init();
    $url = "https://some_server/Login";
    $host = parse_url($url, PHP_URL_HOST);
    //$path = parse_url($url, PHP_URL_PATH);
    $xml_data = "<?xml version='1.0' ?>".
                "<authorization>".
                "<username><![CDATA[some_name]]></username>".
                "<password><![CDATA[some_password]]></password>".
                "<domain><![CDATA[some_domain]]></domain>".
                "</authorization>";
    $headers = array(
            "Content-type: text/xml",
            "Accept: */*,text/xml",
            "User-Agent: dsaxess/special",
            "Host: ".$host,
            "Content-length: ".strlen($xml_data),
            "Expect: 100-continue",
            "Connection: Keep-Alive"
    );
    //var_dump($headers);
    //var_dump($xml_data);
    curl_setopt($ch, CURLOPT_URL,$url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch,CURLOPT_BINARYTRANSFER,true);
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $xml_data);
    $data = curl_exec($ch);
    if (curl_errno($ch)) {
        print "Error: " . curl_error($ch);
    } else {
        var_dump(curl_getinfo($ch,CURLINFO_HTTP_CODE));
        //var_dump($data);
        curl_close($ch);
    }

C# 代码提供"状态正常"和有效的身份验证令牌。PHP 代码给出状态 401 和错误：用户不存在。

我不知道为什么不同。我比较了两者的请求和响应标头，一切看起来都一样。

请帮忙。