Start with status
Check whether the URL responds, which status code appears, and whether the final URL is the one you expected. Then review redirects, DNS, SSL, and response time.
Compare signals
A site can be up for one visitor and blocked for another because of DNS cache, firewall rules, region, hosting provider issues, or CDN configuration.
Common mistakes
Do not assume one failed check proves a global outage. Test from more than one network or monitoring source when the result matters.
FAQ
Does a 200 status mean everything works?
No. It only means the server returned a successful HTTP status for that request.
Can DNS cause downtime?
Yes. Wrong or stale DNS records can send visitors to the wrong place.