HTTP 522 – Connection Timed Out
(Cloudflare) Cloudflare could not negotiate a TCP handshake with the origin server in time.
Common use case
A common symptom of an overloaded origin server, an aggressive firewall silently dropping Cloudflare's IPs, or general network congestion between Cloudflare and the origin.
History
A Cloudflare-specific extension.
Did you know?
It is one of Cloudflare's most frequently reported errors, and Cloudflare's own troubleshooting docs specifically call out overly strict firewall rules as the top cause.