Paypal sandbox IPN return INVALID

Question

I am trying IPN callback, using servlet. The code I am using is provided by paypal for verifying the ipn data. But every time i getting a INVALID response.

Here is the code:

Enumeration en = req.getParameterNames();
String str = "cmd=_notify-validate";

    while (en.hasMoreElements()) {        
        String paramName = (String) en.nextElement();
        String paramValue = req.getParameter(paramName);

//str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue,"UTF-8"); // for UTF-8 i set the encode format in my account as UTF-8
//str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue,"ISO-8859-1");// for ISO-8859-1 i set the encode format in my account as ISO-8859-1
str = str + "&" + paramName + "=" + URLEncoder.encode(paramValue); //default as provided by paypal

    }
    URL u = new URL("http://www.sandbox.paypal.com/cgi-bin/webscr");
    URLConnection uc = u.openConnection();
    uc.setDoOutput(true);
    uc.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
    PrintWriter pw = new PrintWriter(uc.getOutputStream());
    pw.println(str);
    pw.close();

    BufferedReader in = new BufferedReader(new InputStreamReader(uc.getInputStream()));
    String res = in.readLine();
    in.close();

    if (res.equals("VERIFIED") || !res.equals("VERIFIED")) {
        //Update database...
    } else if (res.equals("INVALID")) {      
       //INVALID   
    }

I have checked all three possibilities provided by paypal in case paypal return INVALID as follow:

1) Missing Parameters - As I am send all the parameters no issue of missing parameters

2) Invalid URL. - I am using sandbox so URL is : http://www.sandbox.paypal.com/cgi-bin/webscr

3) Character encoding. - Tried with character encoding same as paypal account setting parameter encoding.

the request I am sending back to paypal using following parameters:

cmd=_notify-validate&last_name=User&test_ipn=1&address_name=Test+User&txn_type=web_accept&receiver_email=sellr1_1252495907_biz%40gmail.com&residence_country=US&address_city=San+Jose&payment_gross=&payment_date=01%3A55%3A04+Sep+26%2C+2009+PDT&address_zip=95131&payment_status=Completed&address_street=1+Main+St&first_name=Test&payer_email=buyer1_1252495751_per%40gmail.com&protection_eligibility=Eligible&payer_id=BXBKS22JQCUWL&verify_sign=AOMkeg7ofCL7FJfioyWA19uCxD4XAgZirsjiGh8cUy1fd2YAqBwOkkst&payment_type=instant&business=sellr1_1252495907_biz%40gmail.com&address_country_code=US&mc_fee=0.64&address_status=confirmed&transaction_subject=True+Up&quantity=1&notify_version=2.8&mc_currency=EUR&custom=&address_state=CA&payment_fee=&handling_amount=0.00&payer_status=verified&shipping=0.00&item_name=True+Up&tax=0.00&username=hannonj&charset=windows-1252&item_number=567&mc_gross=10.00&txn_id=7F456350BS7942738&receiver_id=MASSU6BSR9SC2&address_country=United+States

Please , can any one direct me to proper direction? I am not getting what is wrong the code or the URL or anything else. I tried all the possibilities. Please help me.

Answer 1

An “INVALID” message is due to the following reasons:

• Check that your are posting your response to the correct URL, which is https://www.sandbox.paypal.com/cgi-bin/webscr or https://www.paypal.com/cgi-bin/webscr, depending on whether you are testing in the Sandbox or you are live, respectively.
• Verify that your response to the test IPN message contains exactly the same variables and values as the test message and that they are in the same order as in the test message. Finally, verify that the original variables are preceded by a cmd=_notify-validate variable.

• Ensure that you are encoding your response string and are using the same character encoding as used by the test IPN message. (for example, I can see that he is using letters with umlaut and other symbols like “/”, etc). With regard to the last point, the merchant can try to change the encoding language in use in his PayPal account, following the steps below:

  1. Login on you PayPal account
  2. Click on Profile
  3. Click on “My Selling Preferences” tab
  4. Click on “PayPal Button Language Encoding” (at the end of the page)
  5. Click on "Other Options"
  6. Select from the drop down menu: UTF-8
  7. Choose the same charset also for the second option, which is related to IPN
  8. Click “Save”

If the issue persists, we recommend to review the script in use, PayPal has some IPN code samples available at: https://github.com/paypal/ipn-code-samples

For additional information I include the link: https://developer.paypal.com/webapps/developer/docs/classic/ipn/integration-guide/IPNTesting/#id091GFE00WY4