DNS error

Also searched as: dns lookup failed

Updated 9 October 2026

Short answer

DNS turns names like example.com into the addresses computers connect to. A DNS error means that lookup failed. First check whether it fails everywhere (a problem with the domain) or only on your network or device (your router, ISP, VPN or cache). Then read which kind of failure it is: "doesn't exist" (NXDOMAIN) points to missing records or an expired domain; "timed out" or "server failure" (SERVFAIL) points to the domain's nameservers.

What's the problem

The browser shows DNS_PROBE_FINISHED_..., "DNS lookup failed" or "server not found", or an app can't connect to an address by name.

Why it happens

  • The name doesn't exist: typo, expired domain, or missing record. See NXDOMAIN.
  • The domain's nameservers are broken or unreachable (SERVFAIL or timeouts). See nameserver error.
  • DNSSEC problems after changing DNS providers.
  • Your own network: a router, ISP DNS, VPN, or firewall failing lookups.
  • A cached bad answer on your device.

How to fix it

  1. Try another network (mobile data). If it works there, the problem is your network or device.
  2. Look the name up with a public DNS checker and note the result: answer, NXDOMAIN, or SERVFAIL.
  3. For NXDOMAIN, check the domain and add the missing record.
  4. For SERVFAIL or timeouts, check the nameservers and DNSSEC.
  5. For local problems, restart the router, flush your DNS cache, or switch your device to a public DNS resolver.

What Preventionlabs checks

One click runs the full report on your domain. For this problem it shows your DNS: nameservers, addresses, DNSSEC, and records pointing at services that no longer exist; your domain's registration and expiry date; whether your site loads, how fast, and where its redirects go. With Cloudflare connected, it also shows DNS changes in the last 7 days.

Run your free report

Your first report is free, no card needed. Then A$50 a month, up to 10 domains. Read-only: it never changes anything.

Sources

  1. MDN Web Docs: DNSglossaryDNS maintains a list of domain names along with the resources, such as IP addresses, that are associated with them.
  2. IETF: NXDOMAIN: There Really Is Nothing Underneathstandard (RFC 8020)This document states clearly that when a DNS resolver receives a response with a response code of NXDOMAIN, it means that the domain name which is thus denied AND ALL THE NAMES UNDER IT do not exist.

Related

DNS not resolving: NXDOMAIN NXDOMAIN means DNS says the name doesn't exist at all. Usually a typo, an expired domain, a missing record for that subdomain, or broken nameservers. Domain not working Check three things in order: the domain hasn't expired, its nameservers are the ones you expect, and its DNS records point at your current host. Nameserver error The nameservers listed for your domain aren't answering correctly. Usually they don't match your DNS provider, or the provider doesn't have your domain set up. DNS propagation: how long it takes A record change reaches everyone within its TTL, often minutes to hours. A nameserver change can take up to 24 hours. Here's how to check and speed it up.
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