DNS Errors (NXDOMAIN, SERVFAIL): Why a Site Won't Resolve and How to Fix It

Learn what DNS errors mean, why NXDOMAIN and SERVFAIL happen, how propagation works, and step-by-step fixes when a domain won't resolve.

What NXDOMAIN / SERVFAIL actually mean

NXDOMAIN: this name has no DNS records — typo, expired domain, or wrong nameservers. SERVFAIL: resolvers tried but authoritative servers failed (DNSSEC breakage, lame delegation).

Fixes in order

1) Retype the domain and try https://. 2) Flush local DNS / try mobile data (rules out your resolver). 3) Check WHOIS expiry. 4) For owners: verify NS glue, SOA serial, DNSSEC DS records.

Propagation vs outage

Real propagation takes minutes–hours, not 48h in 2026. If only your network fails, it's your resolver — switch to 1.1.1.1 to confirm.

Test it now: run a live check → then re-read your result with this guide. Each check + guide read is another pageview that funds the free tool.

FAQ

How do I confirm a DNS problem?

Our checker reports “DNS couldn't resolve” distinctly from timeouts. Pair that with a WHOIS lookup.

Why does it work on my phone but not Wi-Fi?

Stale router/resolver cache. Reboot router or change DNS to 1.1.1.1 / 8.8.8.8.