Got 'IPN was not sent, and the handshake was not verified.' while using IPN simulator

[spockyao]

Hi,

I always got "IPN was not sent, and the handshake was not verified." and I have no idea how to resolve it.

The manual from IPN simulator just said "The IPN Simulator itself will display an IPN sent successfully message, as long as the value set in the IPN handler URL field is a valid URL, even if there is no listener at the URL, or even if there is a listener there and it's not working correctly."

I am pretty sure the url is valid, I also check the certification and connection of the server, the cert info is as described as following:

Certificate - valid and trusted

    The connection to this site is using a valid, trusted server certificate issued by Let's Encrypt Authority X3.

Connection - secure (strong TLS 1.2)

The connection to this site is encrypted and authenticated using TLS 1.2 (a strong protocol), ECDHE_RSA with P-256 (a strong key exchange), and AES_128_GCM (a strong cipher).

Also, I have confirmed the Instant payment notifications has been set as enabled with the same url.

The url I was used to test just a blank page return response with status 200 and protocol version http 1.1.

Please help me resolve it.

[spockyao]

Hi,

Anyone could help me?

[ELSC]

Same in August 2019

[Houmanca]

its ridiculous, why Paypal doesn't care about the very old issue? it began back to 2016

[SteveStuartDJ]

Perhaps you've solved this issue as I's a bit of an oldie, but I was searching for something else and I came across your plea.
Out of frustration really, because, as you say, nobody seems to give a stuff about our sales going west.
See my screenshot, where I've made alterations to the buyer verification, it produced a hand shake for me. IPN simulator | PayPal Developer