PayPal Sandbox Classic API Express Checkout Internal NVP Server Error (500)

Question

Short description :

I am developing an e-commerce site using PHP. He uses PayPal to make payments. I have successfully used (from sending a query string through SetExpressCheckout to DoExpressCheckoutPayment to GetExpressCheckoutDetails to store payment data in a MySQL database). PayPal Sandbox mode with their classic API Validation (NVP) from late last year to the present. All this worked until the last night, and no major changes occurred in the PayPal section of the site. Now I get an "Internal Server Error" at https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=[TOKEN] for each payment request.

Step by step

• Request processing request: "... & PAYMENTREQUEST_0_PAYMENTACTION = ...",
• Call "SetExpressCheckout",
• Get [ACK] => Success (no error = no LONGMESSAGE),
• Redirection to the provided token https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=[TOKEN] ,
• Get the "Internal Server Error" from the link above each time.

What i see :

Refund PayPal SetExpressCheckout:

Array ( [TOKEN] => XX-XXXXXXXXXXXXXXXXX [TIMESTAMP] => 2015-03-28T20:27:25Z [CORRELATIONID] => XXXXXXXXXXXXX [ACK] => Success [VERSION] => 109.0 [BUILD] => 15840636 ) 

Sandbox Sandbox error message from the link above:

 Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator, [e-mail] and inform them of the time the error occurred, and anything you might have done that may have caused the error. More information about this error may be available in the server error log. 

Why I can not find the answer :

• The error message “Internal server error” means that I don’t know where to start, as I’m not sure if the problem is with me (which would be my default assumption) or with PayPal.
• Most solutions point to a mismatch between production data and the URL / API sandbox. It's not a problem. I have successfully used Sandbox credentials via the Sandbox link for some time.
• All the problems with the PayPal Internal Server internal error that I found are for people using the REST API (or IPN). I am using the Express-Check version controlled by the Classic-API and I do not see the debug_id return or how I will receive it.
• All problems in the past could be resolved by looking at the returned error message (ACK = Failure & L_ERRORCODE0 = ['some error code'] & L_SHORTMESSAGE0 = ['short error message] & L_LONGMESSAGE0 = [' detailed description of the error message '] ) There is no error message as it is being registered as successful.
• I tried changing the API credentials and getting the standard security headers error (then I will return and the error will disappear and return to the internal server error when redirecting).
• I tried redoing the query string, but I feel pretty confident that this is not a problem, because when I intentionally messed it up, I got a standard error message for this.

Answer 1

After reporting this issue with the magazine on PayPal, they responded by confirming that this is a known issue at their end.

Dear Philip,

Thank you for contacting PayPal Merchant Technical Support for an internal server error in the sandbox environment. This well-known is being investigated and, hopefully, will be in the near future. I will inform you when I have a fixed problem confirmation. Thanks.

Yours faithfully,

Mike

Merchant Technical Support

PayPal, eBay Company

Update from PayPal:

Dear Philip, the sandbox problem should be resolved now, and you should not see the Internal Server 500 error. If you have other questions, please let us know, https://www.paypal.com/mts

Yours faithfully,

Mike

Merchant Technical Support

PayPal, eBay Company

I tested and it seems to be fixed.

Answer 2

Internal server error means internal PayPal server. This is PayPal "Help! I give up!" error message.

This does not exclude the possibility that you did something wrong, which led the PayPal code from the green path and to the forest where it was eaten by the bear, but independently: do as the error page says and contacts PayPal support. They should be able to look up your correlation identifier and see what happened. Then they can tell you if you can solve the problem by making changes at the end or if your code will be good and that is 100% their problem. And then they can improve their code so that the next person who can make a mistake like yours gets the best feedback.

(Although in the case of such a page, which is usually displayed to your client, and not to you, PayPal usually gives only a message about a generic rejection.)

And a few more things I would like to check to see if you want to work on this a bit while you wait until PayPal gets back to you: you have confirmed that the API seems to work as it claims. A reasonable thing to check, but the error in redirecting to the Internet is so focused on this: what do you get if you transfer a known dummy token? What happens on another computer or after clearing cookies? What do you get if you try to make a payment using a button (not an express statement) using the same pair of accounts?