通过 PHP CURL 问题集成文档:调用网络服务时出错，状态为:0

美好的一天，我是通过 PHP curl 进行此文档签名API集成的新手，我想尝试这种集成。我从 http://iodocs.docusign.com/APIWalkthrough/requestSignatureFromDocument 复制了下面的代码，希望我可以轻松测试和理解集成的工作原理。但不幸的是，总是发生错误"调用网络服务时出错，状态为：0"。我已经尝试了其他解决方法，例如将标头格式从XML更改为JSON，但仍然显示错误。请帮忙。

    // Input your info here:
$integratorKey = 'XXXX-9999X9XX-X999-9999-99X9-9X9999X9XX9X';
$email = 'name@domain.com';
$password = 'samplepassword';
$name = 'Sender Full Name';
// construct the authentication header:
$header = "<DocuSignCredentials><Username>" . $email . "</Username><Password>" . $password . "</Password><IntegratorKey>" . $integratorKey . "</IntegratorKey></DocuSignCredentials>";
/////////////////////////////////////////////////////////////////////////////////////////////////
// STEP 1 - Login (to retrieve baseUrl and accountId)
/////////////////////////////////////////////////////////////////////////////////////////////////
$url = "https://demo.docusign.net/restapi/v2/login_information";
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, array("X-DocuSign-Authentication: $header"));
print_r(curl_getinfo($curl));
echo "<br/>";
$json_response = curl_exec($curl);
$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ( $status != 200 ) {
    echo "error calling webservice, status is:" . $status;
    exit(-1);
}
$response = json_decode($json_response, true);
$accountId = $response["loginAccounts"][0]["accountId"];
$baseUrl = $response["loginAccounts"][0]["baseUrl"];
curl_close($curl);
//--- display results
echo "'naccountId = " . $accountId . "'nbaseUrl = " . $baseUrl . "'n";
    /////////////////////////////////////////////////////////////////////////////////////////////////
    // STEP 2 - Create an envelope with one recipient, one tab, and one document and send
    /////////////////////////////////////////////////////////////////////////////////////////////////
    $data = array (
    "emailBlurb" => "This comes from PHP",
    "emailSubject" => "API Signature Request",
    "documents" => array(array( "documentId" => "1", "name" => "testDS.pdf")),
    "recipients" => array( "signers" => array(
            array(      "email" => $email,
                        "name" => $name,
                        "recipientId" => "1",
                        "tabs" => array(
                                "signHereTabs" => array(
                                        array(
                                            "xPosition" => "100",
                                            "yPosition" => "100",
                                            "documentId" => "1",
                                            "pageNumber" => "1"
                                         )
                                    )
                            )
                    )
            )
    ),
"status" => "sent");  
$data_string = json_encode($data);  
$file_contents = file_get_contents("testDS.pdf");
$requestBody = "'r'n"
."'r'n"
."--myboundary'r'n"
."Content-Type: application/json'r'n"
."Content-Disposition: form-data'r'n"
."'r'n"
."$data_string'r'n"
."--myboundary'r'n"
."Content-Type:application/pdf'r'n"
."Content-Disposition: file; filename='”testDS.pdf'"; documentid=1 'r'n"
."'r'n"
."$file_contents'r'n"
."--myboundary--'r'n"
."'r'n";
// *** append "/envelopes" to baseUrl and as signature request endpoint
$curl = curl_init($baseUrl . "/envelopes" );
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $requestBody);                                                                  
curl_setopt($curl, CURLOPT_HTTPHEADER, array(                                                                          
    'Content-Type: multipart/form-data;boundary=myboundary',
    'Content-Length: ' . strlen($requestBody),
    "X-DocuSign-Authentication: $header" )                                                                       
);
$json_response = curl_exec($curl);
$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ( $status != 201 ) {
    echo "error calling webservice, status is:" . $status . "'nerror text is --> ";
    print_r($json_response); echo "'n";
    exit(-1);
}
$response = json_decode($json_response, true);
$envelopeId = $response["envelopeId"];
//--- display results
echo "Document is sent! Envelope ID = " . $envelopeId . "'n'n"; 

我的集成商密钥是否有可能无效？ 如果是，我有什么方法可以检查我的集成商密钥是否有效？在创建我的集成器密钥时，我只是按照此链接中的过程进行操作 http://www.docusign.com/developer-center/quick-start/first-api-call