Some time ago I set up a page on my in-progress web site for purchase processing with PayPay using IPN and a Sandbox account.
Everything was working fine, mock payments were completing successfully, but it's been a couple of months since I last tested this part of the site, and I've suddenly found that it's no longer functioning.
Nothing has changed with the page, but I'm getting an "Internal Server Error" response when my page redirects to the "Sandbox URL": https://www.sandbox.paypal.com/cgi-bin/webscr
I frequently find myself going around in circles with the PayPal documentation, there often appear to be two or more entirely separate documents describing the same procedure, and with conflicting information.
For example, this page describes the IPN testing process as I've been following it to date: https://www.paypal.com/cgi-bin/webscr?cmd=p/sell/ipn-test-outside
it is the URL provided by this page that is now returning the 500 Internal Server Error message. But I've subsequently discovered this page: https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNTesting/#sandbox
which indicates an entirely different Sandbox URL. The latter looks more up-to-date, but changing my URL to redirect here results in a "Secure Connection Failed" message in FireFox (ERR_CONNECTION_RESET in Chrome).
Are both of these URLs invalid? Is the Sandbox site presently not processing payments? The situation is very confusing and I can't figure out what might be wrong.
Thank you for any advice.
