Hi,

My client uses WooCommerce with the Authorize.net DPM plugin. They are seeing relay response timeouts intermittently.

So far, I've done the following:

• Verified that there are no errors in the web server logs
• Verified that no host-based firewalls are blocking the connections (iptables or fail2ban)
• Verified that I can access the Relay Response URL from my own computer. I get the expected error of "Not Authorize.net"
• I made this host the default Vhost, so that clients without SNI (such as Authorize.net) can access with HTTPS. However, I still see this issue when the relay response URL is not using HTTPS.
• I increased the TTL of the DNS record to 1 week.

I still see some timeouts. I have a cronjob set up to run a test transaction to the sandbox every 30 minutes, using the production relay response URL. Some of the tests time out, and some of the customer transactions time out.

This server is hosted on Amazon Web Services, so I've enabled the VPC flow logs. When I get a timeout, I see no traffic from the 198.241.x.x. If no traffic reaches my network, I'm unable to do much more. I had contacted Authorize.net support to get more information on the failures, but did not get anything from them.

Does anyone have additional suggestions, or know how I can get more insight from Authorize.net?