Recent problem with PayPal payments

Great. Thanks for sharing the info. And Yes, the system needs to receive PayPal IPN Messages so that it knows about payment and do the process further. If the server's firewall blocks the message, it won't work

Tuan

Thanks for the help Nomis! I've gone into Cloudflare and whitelisted all of those IP's. Now just waiting for the next PayPal payment to come through and I'll report back. 

So I whitelisted all of the IP's and still having issues. One or two subs will creep through and then some won't even register. It seems to be a deeper issue.

do you have a local firewall such as CSF or similar? something that combats brute force or layer7 flooding?

If so you should try to whitelist all of cloudflare IPs www.cloudflare.com/en-gb/ips/
(as you said cloudflare is infront of your site). In CSF this is /etc/csf/csf.allow

then reload the firewall.

That eliminates callbacks being blocked from certain CF servers (firewalls could have auto flood blocked individual CF servers reaching your origin which could cause intermittent connectivity issues on new requests, such as IPN callbacks.

Also might want to switch your domain name to use ipv4 only (A records not AAAA) for a while to see if ipv6 is a problem.

Hi Nomis, I'm not aware of any additional firewalls on the server. I've attached an image of the Firewall rules I've setup. 

Fingers crossed, everything seems to be working normally again. I'm going with Cloudflare needing time to accept the new IP whitelist settings. I'll be glad to see the end of this month!

If anyone is going through similar issues and using Cloudflare, maybe this thread will help.

Thanks Mark for sharing and happy to hear that the issue finally got sorted. Sadly, I don't have any experience with server management to be able to give good suggestions for.

Tuan