IPN Simulator: “IPN was not sent, and the handshake was not verified. Please review your information.”

Question

I\'m getting the following error when using the IPN Simulator -

IPN was not sent, and the handshake was not verified. Please review your information.

Answer 1

Check web access logs on your server. In my case there were 500 Internal Server Error on my side and I got same message in IPN Simulator. But IPN Simulator were trying to send request any way...