ERROR: Unable to verify $_POST vars.

I have been using the s2member pro to sell content on specific pages for viewing using paypal. The transaction works fine and the email to the customer with the link to the product page works fine but when I process the payment with paypal rather than redirect back to the product page it gives me this error:
ERROR: Unable to verify $_POST vars.
Please contact Support for assistance.

This is most likely related to an invalid configuration of s2Member, or a problem with server compatibility. If you are the site owner, and you’re absolutely SURE that your configuration is valid, you may want to run some tests on your server, just to be sure $_POST variables are populated, and that your server is able to connect/communicate with your Payment Gateway over an HTTPS connection.

s2Member uses the WP_Http class for remote connections; which will try to use cURL first, and then fall back on the FOPEN method when cURL is not available. On a Windows® server, you may have to disable your cURL extension; and instead, set allow_url_fopen = yes in your php.ini file. The cURL extension (usually) does NOT support SSL connections on a Windows® server.

Please see this thread for details regarding the ideal server configuration for s2Member.

I followed your threads and even talked with technical support with my hosting company “inmotion hosting” but no luck. I need help ASAP. Jeff

Hey its been over 19 hours I need help. I followed your instructions via the other forum posts and it completely crashed my site. I need to get this to work today!!!!!!!!!!!

Thank you for reporting this important issue.

I am reviewing this thread now.

To fix your issue we will need to see your log files. Do you have logging enabled?

See: Dashboard -› s2Member® -› PayPal® Options -› Account Details -› Logging

The Unable to verify $_POST vars error is normally caused by the following things:

1. An invalid custom attribute in your shortcode
* The custom attribute should always be EXACTLY the same as the site’s URL
* To ensure that this is not the problem, please send us your log files and the shortcode that you’re currently using to sign Users up

2. An invalid server setup, as mentioned in the error message:

If you are the site owner, and you’re absolutely SURE that your configuration is valid, you may want to run some tests on your server, just to be sure $_POST variables are populated, and that your server is able to connect/communicate with your Payment Gateway over an HTTPS connection.

s2Member uses the WP_Http class for remote connections; which will try to use cURL first, and then fall back on the FOPEN method when cURL is not available. On a Windows® server, you may have to disable your cURL extension; and instead, set allow_url_fopen = yes in your php.ini file. The cURL extension (usually) does NOT support SSL connections on a Windows® server.

Please send your log files (if you did not have logging enabled, please run another test transaction), and a Dashboard Login via our Private Contact Form.

s2Member® » Private Contact Form

Hey its been over 19 hours I need help. I followed your instructions via the other forum posts and it completely crashed my site. I need to get this to work today!!!!!!!!!!!

What forum posts are your referring to here? We are unaware of any solutions that may cause issues to your WordPress installation. Could you please clarify exactly what you did to cause your site to “crash”?