You're both sort-of correct. AO kicks in on specific 5xx error codes: 502, 504, and then Cloudflare's 52x codes. It doesn't kick in on 500 or 503, or 4xx errors

You're both sort-of correct. AO kicks in on specific 5xx error codes: 502, 504, and then Cloudflare's 52x codes. It doesn't kick in on 500 or 503, or 4xx errors. Ref: https://support.cloudflare.com/hc/en-us/articles/202238800-Why-is-Always-Online-not-working- https://support.cloudflare.com/hc/en-us/articles/202238800-W...