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


I referred all the previous stackoverflow answers regarding this. but I am not clear what to do with my case.

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

This is the error I am getting when sending ipn message using ipn simulator..

I am using the script from


I am just checking this with sandbox account

and I am not using https site. I am using only http.

even I tried

             CURLOPT_URL => $url,
                    CURLOPT_POST => TRUE,
                    CURLOPT_POSTFIELDS => http_build_query(array('cmd' => '_notify-validate') + $ipn_post_data),
                    CURLOPT_RETURNTRANSFER => TRUE,
                    CURLOPT_HEADER => FALSE,
                    CURLOPT_SSL_VERIFYPEER => TRUE,
                    CURLOPT_CAINFO => 'cacert.pem',

cacert.pem contains https://www.symantec.com/content/dam/symantec/docs/other-resources/verisign-class-3-public-primary-certification-authority-g5-en.pem

even I changed the CURLOPT_SSL_VERIFYPEER to false but didn't work

I don't know what to do please help

update: I removed everything in the listener page and put just file_put_contents("ipntest.txt", var_export($_POST, true)); still the same error and ipntest.txt file is alse not created Thanks,

As of now (March 2017) IPN Simulator doesn't seem to work at all. Use Sandbox accounts to initiate normal payment cycle; it does work.