We have migrated to wpengine servers and the PayU payment system stopped transmitting transaction status correctly.
I have contacted PayU support, who says that Cloudflare is blocking the traffic and they see that they are receiving HTTP 403 and error code: 1010 in response.
They advised to add IP addresses to the whitelist and to allow the User-Agent header: Jakarta Commons-HttpClient/3.1
IP address list: 22.214.171.124, 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168
We did not make any changes to Cloudflare except to change the CNAME and A records for the “Advanced Network” support of the new WPEngine server, and so far everything has worked.
Of course IP addresses are added to the whitelist, header verification is disabled.
In addition, I added WAF rule to Allow header Jakarta Commons-HttpClient/3.1
I also contacted the WPEngine hosting to verify that they are the ones blocking the incoming traffic, however, they do not see any connection or header I mentioned earlier.
PayU is not receiving the correct confirmation making the orders have a status of “On Hold” instead of “Processing”