[SOLVED] Some Paypal IPN's are failing

Hi. We received an email from paypal yesterday informing us that some paypal ipn's processed by CBSubs are failing - please see the email below. We are using Joomla 3.3.3, CB 1.9.1, CBSubs 3.0.0. Most of the CBSubs transactions are processed successfully. I have also attached: a transaction record from paypal for one of the failing ipn's; a screenshot of the CBSubs Basket screen; and a screenshot of the CBSubs Notifications screen.

Can you please provide some advice/recommendations for how to debug this? Thanks!

I don't know if this is your case, but I had the same problem and eventually discovered that some of the IPs I had blocked because of spamming and hacking had been purchased by Paypal. Transactions are completed differently each time. You will have to contact your host find out the IPs that are giving you that error and then unblock them. Like said, this was my situation and it fixed the problem. I have no idea if there is a different issue in your case.

In our case, the paypal payment is completed in paypal but the paypal IPN is apparently not getting back through our server to be processed by CBSubs. I contacted our web host and their engineer made some change to whitelist something (I think he whitelisted the paypal ipn url???) Maybe that will fix our problem but web host (liquidweb) engineer was not completely confident. Is there any advice from joomlapolis on how to resolve this? Thanks!

Looks like your host is blocking the IPNs. They're inbound POST/GET requests and some hosts have very strict rules in this regard and will block inbound connections. If they don't reach CBSubs at all this is nearly guaranteed to be the case and I believe is the only reason that will prompt PayPal to send such emails. Do the IPNs show up within CBSubs > Notifications at all? If they do are there any errors regarding them in CBSubs > History Log?

We are no longer receiving the "failing IPN" emails from PayPal and the transactions are completing successfully.

When we first had the problem the IPNs did not show up CBSubs notifications and I had to complete a subscribers transaction in CBSubs manually (the paypal payment was actually received successfully.) After that, the IPNs did show up in CBSubs notifications and the transactions completed but we received the paypal "failing IPN" emails.

I worked with our host on this and got different information from different engineers. One said he found an error in a server log and whitelisted the IPN URL. But we still got the paypal emails and a different engineer said he couldn't find any errors in the server logs.

Anyway, we're good (for now.)

Thanks.