设置Express Checkout方法在ack中返回失败

Question

I want to do the express checkout process in the paypal for the customers without redirecting the browser. I have written the code like

        string sAPIUser = apiuser;
        string sAPIPassword = password;
        string sAPISignature = "signature";
        string sAPIEndpoint = "https://api-3t.sandbox.paypal.com/nvp";           
        string sAppID = "APP-80W284485P519543T";

        StringBuilder sRequest = new StringBuilder();

        ASCIIEncoding encoding = new ASCIIEncoding();
        string postData = ("&METHOD=SetExpressCheckout");
        postData += ("&VERSION=63.0");
        postData += ("&PAYMENTREQUEST_0_AMT=10.00");
        postData += ("&PAYMENTREQUEST_0_CURRENCYCODE=USD");
        postData += ("&PAYMENTREQUEST_0_PAYMENTACTION=Sale");
        postData += ("CANCELURL=http://www.google.com");
        postData += ("RETURNURL=http://www.google.com");
        byte[] data = encoding.GetBytes(postData);

// Prepare web request...

   HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(sAPIEndpoint);
   myRequest.Method = "POST";
   myRequest.Headers.Add("X-PAYPAL-SECURITY-USERID", sAPIUser);
   myRequest.Headers.Add("X-PAYPAL-SECURITY-PASSWORD", sAPIPassword);
   myRequest.Headers.Add("X-PAYPAL-SECURITY-SIGNATURE", sAPISignature);
   myRequest.Headers.Add("X-PAYPAL-SERVICE-VERSION", "1.3.0");
   myRequest.Headers.Add("X-PAYPAL-REQUEST-DATA-FORMAT", "NV");
   myRequest.Headers.Add("X-PAYPAL-RESPONSE-DATA-FORMAT", "NV");
   myRequest.Headers.Add("X-PAYPAL-APPLICATION-ID", sAppID);
   myRequest.ContentType = "application/x-www-form-urlencoded";
   myRequest.ContentLength = data.Length;
   // Send the request, read the response
   Stream newStream = myRequest.GetRequestStream();
   newStream.Write(data, 0, data.Length);
   newStream.Close();
   HttpWebResponse response = (HttpWebResponse)myRequest.GetResponse();
   Stream responseStream = response.GetResponseStream();
   Encoding encoding2 = Encoding.GetEncoding("utf-8");
   StreamReader reader = new StreamReader(responseStream, encoding2);
   string theResponse = reader.ReadToEnd();
   theResponse = HttpUtility.HtmlDecode(theResponse);

But i am getting the failure message in the theResponse variable. What error i am doing. The error is like

    TIMESTAMP=2013%2d03%2d05T05%3a55%3a38Z&CORRELATIONID=5c10035aca937&ACK=Failure&VERSION=63%2e0&BUILD=5331358&L_ERRORCODE0=10002&L_SHORTMESSAGE0=Authentication%2fAuthorization%20Failed&L_LONGMESSAGE0=You%20do%20not%20have%20permissions%20to%20make%20this%20API%20call&L_SEVERITYCODE0=Error

How can i rectify this.

Answer 1

Make sure that the credentials you are using are for your sandbox account and not your live account. Your code looks like it is pointing to the sandbox, so you would need to use your sandbox credentials. Also, if this is not all of your code, make sure you are not passing across a variable called "SUBJECT" and populating it with an email address.