Yes. 5xx codes are server errors: The server failed to fulfil a valid-looking request.

5xx · Server errorNot part of the HTTP standard

HTTP 522 Connection Timed Out

Cloudflare: it couldn't connect to the origin in time.

Example response

HTTP

HTTP/1.1 522 Connection Timed Out
Content-Type: application/json; charset=utf-8

{ "error": "Connection Timed Out" }

Look up the headers shown here in the HTTP headers reference.

What does HTTP 522 mean?: Connection Timed Out. Cloudflare: it couldn't connect to the origin in time.
Is 522 an error?: Yes. 5xx codes are server errors: The server failed to fulfil a valid-looking request.