Intermittent IPN Failure

I’ve got a client site that is receiving intermittent IPN Failure emails from Paypal. I’ve checked that the IPN settings match in s2member and Paypal. Here’s the paypal-ipn.log:

PHP v5.2.17 :: WordPress® v3.4.2 :: s2Member® v120703 :: s2Member® Pro v120703
Memory 49.18 MB :: Real Memory 49.75 MB :: Peak Memory 49.28 MB :: Real Peak Memory 49.75 MB
legacymovement.net/?s2member_paypal_notify=1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.94 Safari/537.4
array (
  's2member_log' => 
  array (
    0 => 'Unable to verify $_POST vars. This is most likely related to an invalid configuration of s2Member, or a problem with server compatibility.',
    1 => 'If 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.',
    2 => '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.',
    3 => 'Please see this thread: `http://www.s2member.com/forums/topic/ideal-server-configuration-for-s2member/` for details regarding the ideal server configuration for s2Member.',
    4 => 'array (
  \'s2member_paypal_notify\' => \'1\',
)',
  ),
)

Please advise.

Thanks!

Hello Brian,

Could you please put the following script in your main WordPress folder, and open it in a browser: http://www.s2member.com/r/server-check/

It should tell you if there’s anything wrong with your server, as the error suggests.

– Eduan

Thanks, will do, although I think I may have found the issue with another account we host getting hacked.

I see, well hope nothing important was hacked, and hope you solve the problem. :)

Fixed the hack, but I’m still getting the IPN Failure. I uploaded the server scan script and I’ve got all green checks.

Looking on the Paypal side at IPN History, each of the failed notifications lists the HTTP Response as 403. I don’t know why this would be happening.

Any suggestions?

Here’s an article you can check regarding that error: Knowledge Base » Mod Security, Random 503/403 Errors

Hope this helps. :)

I read that article, however I could not find any reference to mod_security in my httpd.conf.

Then I’m afraid I’m not sure what the problem could be. :/

Brian,

If PayPal is reporting the IPN HTTP Response as 403, that means PayPal is trying to send an IPN message to your IPN URL (see Dashboard -› s2Member® -› PayPal® Options -› PayPal® IPN Integration) and the web server is returning a 403 (forbidden) error.

I recommend checking with your web host to see if maybe that URL was blocked somewhere (possibility in an .htaccess file or a firewall or the web server configuration).

That was my thought too, however I have no trouble opening my IPN URL in my browser and getting a 200 response. The site is on a VPS, so I’ve got access to everything. Willing to try anything at this point.

The site is at http://legacymovement.net

In that case, the only variable is the route being taken to access the IPN URL… PayPal’s servers try to access it and they get a 403… you try to access it and it’s successful. That means that your web server is probably blocking a PayPal IP address or there’s something else blocking PayPal from requesting the IPN URL.

Have you tested it again recently to confirm this issues is still occurring? It could’ve been a temporary glitch.

Just tested it again in both Chrome from my machine, and by resending the request from Paypal IPN History.

I got a 200 in Chrome.

Paypal failed with a 403.

Got on with my hosting company, we both checked the apache error_log and there are no 403s for the domain in question since Nov 14th.

Any ideas? I’m at a loss. Paypal says it’s getting a 403, but the server doesn’t.

Have you asked PayPal support for help about it? Ask if they can give you the URLs PayPal tried that resulted in the 403, and then show them to your web host support to investigate them.