I have implemented IPN for many years and it has worked fine. I recently went through an upgrade to the site, and I thought it would be nothing to affect the IPN code. Initially, the IPN seemed to be working just fine but then broke on or about June 22nd. Since then I have been trying to fix it. I retested the code that fires when an event comes in and that is working fine. I then tested communication between my server and PayPal using the IPN simulator and have come across some very unusual behavior. If I set up an IPN and only choose web_accept and not any of the other fields, the simulator says that it was able to communicate with my site and the handshake worked. However, my site correctly records an error because all the field are wrong. If however, I fill in all the fields correctly that my site expects and send another IPN, the simulator says: "IPN was not sent, and the handshake was not verified. Review your information." However, if I check my site, the script fires correctly and records the notification updating the database as it should. I also record the message sent back from Paypal and it is sending back VERIFIED to my server. I am confused. Thanks for any help.
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