Every check returns a code. Learn which ones mean the site is healthy, which mean a bot wall (not an outage), and which mean the server is actually struggling.
The classic question. A step-by-step method using an independent checker, a second network, and DNS checks to pinpoint whose side the failure is on.
Browsers block sites with lapsed certs even though the server is fine. Check any certificate's expiry with a live TLS handshake, then automate renewal.
When DNS vanishes but hosting is paid, the domain registration lapsed. Read the expiry timeline and check any domain for free via RDAP.
How uptime is measured, how much downtime each “nine” allows per year, and why a 100% self-check log can still hide real outages.
Diagnose regional blocks, ISP filtering, and geo-restrictions — and combine a VPN with a server-side check to pinpoint the cause.