Error 522 occurs when Cloudflare times out contacting the origin web server. Two different timeouts cause HTTP error 522 depending on when they occur between Cloudflare and the origin web server:
Before a connection is established, the origin web server does not return a SYN+ACK to Cloudflare within 15 seconds of Cloudflare sending a SYN.
After a connection is established, the origin web server doesn’t acknowledge (ACK) Cloudflare’s resource request within 90 seconds.
(Most common cause) Cloudflare IP addresses are rate limited or blocked in .htaccess, iptables, or firewalls. Confirm your hosting provider allows Cloudflare IP addresses.
An overloaded or offline origin web server drops incoming requests.
The origin IP address in your Cloudflare DNS app does not match the IP address currently provisioned to your origin web server by your hosting provider.
I have looked at the resource provided, neither seem to apply as the webserver responds to requests at it’s ip address, however the dns server is not following the a record that points to the ip address.