About a month or two ago one of my clients stopped receiving PayPal payment notifications, but was still getting the WooCommerce "Order Received" emails. After a BUNCH of back and forth with PayPal, adjusting our SSL settings and more, we're finally at the point where the IPN messages ARE received by WordPress, but the response isn't received by PayPal, when CloudFlare is active. If I disable the CloudFlare proxy for that domain, then everything works normally.

I don't know if they were just jumping on that as an excuse to close the ticket, but PayPal's response was:

"Using a Proxy service is something that will be blocked due to updated security standards for IPNs. We need to be able to see the IP address and send and receive https responses. When you have a Proxy enabled we are not receiving https responses. "

But that seems like BS to me because it means that CloudFlare, which runs like half the sites on the internet, wouldn't work at all.

Sick of dealing with it I configured WordPress to also respond to ipn.domain.com and set that as the IPN URL in PayPal, but the problem is that WooCommerce is specifying the IPN URL when it sends a request, and it's the URL for the the main domain.

Does anyone have any experience with this, or suggestions? If I could force the IPN url via functions.php, that seems like it might work.