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

5xx · Server errorNot part of the HTTP standard

HTTP 524 A Timeout Occurred

Cloudflare: the origin accepted the connection but didn't respond in time (about 100 seconds).

Example response

HTTP

HTTP/1.1 524 A Timeout Occurred
Content-Type: application/json; charset=utf-8

{ "error": "A Timeout Occurred" }

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

What does HTTP 524 mean?: A Timeout Occurred. Cloudflare: the origin accepted the connection but didn't respond in time (about 100 seconds).
Is 524 an error?: Yes. 5xx codes are server errors: The server failed to fulfil a valid-looking request.