Error guide

NXDOMAIN (DNS name not found)

The DNS resolver answered definitively that the name does not exist — before any connection was attempted.

NXDOMAIN is a DNS response code meaning the queried name does not exist. It is an authoritative negative answer, not a timeout: a nameserver that is responsible for the zone has been asked and has said there is nothing here. No connection was attempted, because there was no address to connect to.

This is one of the most complete failures a service can have. Every client fails at once, none of your servers see any traffic, and your application logs show nothing at all — which is exactly what makes it easy to misdiagnose. From inside the infrastructure everything looks perfectly healthy and idle.

It also has a small set of causes, most of them administrative rather than technical: a domain that expired, a record deleted during a change, a zone that was moved without being fully recreated, or nameservers at the registrar that no longer point at the provider actually hosting the zone.

Common causes

  • The domain registration expired.
  • A DNS record deleted or renamed during a change.
  • Nameserver delegation at the registrar pointing at a provider that no longer hosts the zone.
  • A zone migration where records were not fully recreated at the new provider.
  • A typo in the hostname being queried — the most common cause by far in a monitoring check.
  • A registrar hold or suspension on the domain.

How to diagnose it

  1. Query the name directly with dig or nslookup and read the status line — NXDOMAIN is stated explicitly there.
  2. Check the domain's registration and expiry with a whois lookup before anything else.
  3. Query the zone's authoritative nameservers directly, bypassing caches, to see what they actually hold.
  4. Confirm the delegation at the registrar matches the provider that hosts the zone.
  5. Check nearby names — if the apex resolves and one subdomain does not, it is a record rather than the domain.

Whose fault is it? The network in between

A configuration or registration problem rather than a server failure. Your servers are fine; nobody can find them.

What monitoring sees

A DNS failure is a target signal rather than a network ambiguity, so Uptimely commits it like any other failure rather than treating it as possibly its own problem. Expiry is the cause with the longest warning, and Uptimely does not read registration dates, so preventing it is the registrar's job: turn on auto-renew. A DNS monitor on the record, or the Domain monitor, which confirms the domain still exists, reports the failure the moment it lands.

Related error guides

Terms used on this page

Questions

What is the difference between NXDOMAIN and SERVFAIL?

NXDOMAIN is a definite answer that the name does not exist. SERVFAIL means the resolver could not get an answer at all — a broken zone, a DNSSEC validation failure, or unreachable nameservers. One is a no, the other is a failure to ask.

Why does the site work for me but not for others?

Caching. Your resolver may still hold a valid answer whose TTL has not expired while others are already getting the negative one. Querying the authoritative nameservers directly bypasses this and shows what is really published.

One of the Uptimely HTTP and network error guides, written for the person who operates the server rather than the one refreshing the page. Something here read wrong to you? Email support@getuptimely.com.