What is a 522 error?

A 522 Connection Timed Out is Cloudflare's way of saying it tried to open a TCP connection to the origin server and never got a handshake back. Cloudflare is up, the DNS resolved, the request reached the edge, and then the trail went cold.

Among the Cloudflare error range this is the most clear-cut, and the most reassuring to diagnose.

Why it is almost never about you

The handshake that failed happens between Cloudflare's network and the origin, entirely after your request was accepted at the edge. Your headers, your IP, your fingerprint and your request rate play no part in whether that connection succeeds. A 522 is infrastructure.

Typical causes on the site's side: the origin server is down or overloaded, its firewall is dropping Cloudflare's IP ranges, the server ran out of available connections, or a routing problem sits between the two networks.

This distinguishes it usefully from a 520, where the origin did answer and the answer was unusable, and from a 504, where a connection was established but the response was too slow.

How to handle it in a crawl

Treat it as a site outage rather than a block:

• Back off hard. An origin refusing connections will not be helped by more of them. Exponential backoff with a generous ceiling, and jitter so your workers do not resynchronise.
• Do not escalate. Reaching for residential IPs, a headless browser or a different header set is wasted effort and wasted cost, because none of those change whether Cloudflare can reach the origin.
• Requeue rather than discard. Unlike a 410, a 522 says nothing about whether the page exists. Put the URL back in the queue for a later pass.
• Check the scope. If every URL on one host returns 522 while other hosts are fine, it is that site. If many unrelated hosts return it at once, look at your own network path first.

One thing worth confirming

Very occasionally a site will front different origins for different regions, and one of them is unhealthy while another is fine. If a 522 persists for a host that is clearly online, requesting through a different proxy country is worth one attempt before writing the site off for the day.