You can check the Support pages for detailed information on error 522.
You might be using an alternative to iptables like firewalld.
Can you curl your website directly at the IP?
curl --verbose --header 'Host: example.com' http://192.0.2.1
or if you have a valid certificate and are using Full SSL mode:
curl --verbose https://example.com --resolve 'example.com:443:192.0.2.1'