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.

The URL is non-SSL HTTP (dev environment).

When I hit it in a browser I get the expected output (and a matching entry in my servers access.log), however when I hit it via the IPN Simulator, I get the above error, and nothing in the servers access log.

On advice from these questions:

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

I tried the command openssl s_client -connect api-3t.sandbox.paypal.com:443 -showcerts -CApath /etc/ssl/certs and got the output they suggested:

Verify return code: 0 (ok)

I don't think this is particularly important as I'm not attempting to make an SSL request.

Any other ideas?

I'm attempting this as part of a bug fix, I developed the IPN stuff approximately 3 weeks ago and the IPN Simulator worked just dandily, now not so much.

Thanks in advance.

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.

Answer 2

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...

Answer 3

This is incredible but in my case I needed to add a trailing slash to the end of the URL. Truly incredible.