A 524 error indicates that Cloudflare made a successful TCP connection to the origin web server, but the origin did not reply with an HTTP response before the connection timed out. Review the suggestions in this Community Tip for troubleshooting ideas.
A 520 error occurs when the connection started on the origin web server, but that the request was not completed. The most common reason why this would occur is that either a program, cron job, or resource is taking up more resources than it should causing the server not to be able to respond to all requests properly. Review the Quick Fix Ideas in this Community Tip for troubleshooting suggestions.