Error Message on New Subscriber return from Paypal payment

#1

I have verified my shared hosting is on a LITESPEED server,.

I got this ERROR message on return from signing up a new Paying Member on Paypal site. The redirect back brought up this error message.

ERROR: Unable to verify $_POST vars.
Please contact Support for assistance.:joy:

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.

All my registered users who pay for Membership encounter this message and can’t get access to my website S2Member protected pages.

Note: I am not a programmer.

I’d appreciate explanation and assistance.
Jim

#2

Questions from Tech Support at my hoster for S2Member:

  1. Can S2Member team recommend php version (and modules that may be needed)?

  2. Global variables are off - can they confirm they are not needed?

  3. I can switch between 5.1 and 5.6 - right now 5.4 is running.

#3

That error message can mean many things. Your PHP settings are fine. I would have them switch to 5.6 because 5.4 is at or very near end-of-life (no more security patches).

Question: Are you using HTTPS (SSL) for your connection to PayPal? I have seen several tickets where PayPal had switched to requiring SSL for a customer without warning. In at least two of these cases the site owners were getting the ERROR: Unable to verify $_POST vars error message. If you aren’t using SSL, please contact PayPal and ask them if it is required for your account.

If you are using HTTPS (SSL), please see this KBA and download and run the s2Member Server Scanner.

If that turns up no errors, please triple-check all of your PayPal account settings. Go through each of these s2Member configuration panels in detail, checking both the settings on your site and at PayPal:

  • WordPress Dashboard → s2Member (Pro) → PayPal Options → PayPal Account Details
  • WordPress Dashboard → s2Member (Pro) → PayPal Options → Payflow Account Details (if applicable)
  • WordPress Dashboard → s2Member (Pro) → PayPal Options → PayPal IPN Integrations
  • WordPress Dashboard → s2Member (Pro) → PayPal Options → PayPal PDT/Auto-Return Integration

Let me know if you have any questions.