Your site may return Cloudflare 524 timeout errors right after your Meta (Facebook/Instagram) ads go live.
Why this happens. When Meta approves your ads, Meta’s crawler (user agent facebookexternalhit) sends a large volume of requests in a short window to preview and validate your ad landing pages. Each request carries different tracking parameters in the URL, so none of them are served from Cloudflare’s cache, and every request reaches your origin server at once. That sudden spike can overwhelm the origin and cause 524 timeout errors.