Troubleshooting Cloudflare 1XXX errors

Question

How do I troubleshoot a Cloudflare 1XXX error on my website?

Answer

Cloudflare 1XXX errors indicate an issue with a Cloudflare firewall rule or another issue with the Cloudflare service. For example:

Error 1020 
Access denied

What happened?
This website is using a security service to protect itself from online attacks.

The 1020 Access denied error indicates that a firewall rule on Cloudflare's end is blocking access to the website. The error code, or Ray ID, on the webpage can be searched in the Cloudflare logs to determine the cause of the issue.

Cloudflare's documentation on troubleshooting 1XXX errors:

Cloudflare: Troubleshooting Cloudflare 1XXX errors