524 A Timeout Occurred
HTTP response status code 524 A timeout occurred is an unofficial server error that is specific to Cloudflare. This HTTP status code occurs when a successful HTTP connection was made to the origin server but the HTTP Connection timed out before the HTTP request was complete.
Usage
Cloudflare is a content delivery network that acts as a gateway between a user and a website server. When the 524 A timeout occurred status code is received, it implies that a successful HTTP Connection was made between Cloudflare and the origin server, however the HTTP Connection timed out before the HTTP request was completed. Cloudflare typically waits 100 seconds for an HTTP response and returns this HTTP status code if nothing is received.
Takeaway
The 524 A timeout occurred status code is a Cloudflare-specific server error that is generated because Cloudflare did not receive a HTTP response from the origin server after a HTTP Connection was made.