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

I found out that IP-based http such as http://182.100.25.4/foo/bar/baz do not work. I used dyndns to create a DNS record to point to 182.100.25.4 and suddenly voila - http://somedns.ddns.net/foo/bar/baz started working properly in the IPN simulator. http-based URLs do work, you do not need to use https-based URLs.