If you have ever tried to load a website and were greeted by a message saying "This site can't be reached" or an error code like DNS_PROBE_FINISHED_NXDOMAIN, you have encountered a Domain Name System (DNS) failure.
This guide explains what the NXDOMAIN error means, why it happens, and the specific steps both visitors and website owners can take to fix it.
NXDOMAIN stands for Non-Existent Domain. It is a technical response sent by a DNS server indicating that the domain name you typed simply does not exist in its records.
Essentially, your browser asked the internet's "phonebook" (DNS) for the IP address of a website, and the system replied, "I cannot find an entry for that name".
How It Appears in Different Browsers While the technical cause is the same, browsers display this error differently:
• Google Chrome: Displays DNS_PROBE_FINISHED_NXDOMAIN and "This site can't be reached".
• Mozilla Firefox: Says "Hmm. We’re having trouble finding that site".
• Microsoft Edge: Displays "Hmm… can’t reach this page".
• Safari: States "Safari Can’t Find the Server".
The error can stem from issues on your device (client-side) or problems with the website itself (server-side).
Client-Side Causes (For Visitors)
• Typos: The most common cause is simply misspelling the domain name.
• Outdated Cache: Your browser or operating system might be remembering an old, incorrect IP address for the site.
• DNS Settings: Your Internet Service Provider's (ISP) DNS servers might be slow or unresponsive.
• VPN/Firewall: Security software can sometimes block DNS lookups incorrectly.
Server-Side Causes (For Site Owners)
• Expired Domain: If the domain registration has lapsed, the DNS system removes the records, resulting in an NXDOMAIN error.
• DNS Propagation: If you recently moved your website to a new host, changes can take up to 48 hours to update globally.
• Missing Records: The DNS zone file might lack the necessary "A Records" pointing to the server IP.
If you are trying to visit a website and see this error, try these steps in order:
1. Flush Your DNS Cache Your computer stores DNS results to load pages faster. If these stored results are outdated, you need to clear them.
If you are using a "VPN" or "Secure DNS" feature within your browser (like Chrome’s 'Use secure DNS' setting), standard system-level flushing might not work. You may need to disable the VPN or the browser's private DNS setting to see if that is the source of the conflict.
• Windows: Open Command Prompt as Administrator, type ipconfig /flushdns, and press Enter.
• macOS: Open Terminal, type sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder, and press Enter (you may need your password).
• Chrome: Type chrome://net-internals/#dns in the address bar and click Clear host cache.
2. Release and Renew IP Address This forces your computer to request a fresh connection configuration from your network.
• Windows: In Command Prompt, type ipconfig /release and then ipconfig /renew.
• macOS: Go to System Settings > Network > Details > TCP/IP and click Renew DHCP Lease.
3. Change Your DNS Servers ISP DNS servers can be unreliable. Switching to a public DNS provider often resolves the issue instantly.
• Google DNS: Use 8.8.8.8 and 8.8.4.4.
• Cloudflare DNS: Use 1.1.1.1 and 1.0.0.1.
• How to change: Go to your Network/Adapter settings on Windows or macOS and replace the automatic DNS numbers with the ones above.
4. Check Your Local Hosts File The "hosts" file on your computer can override public DNS. If a program or malware added an entry there, it could block access.
Some antivirus or malware programs modify your "hosts" file to redirect you away from legitimate sites or block them entirely. If you find entries in your hosts file that you didn't put there, run a full security scan on your computer immediately.
• Windows: Open Notepad as Administrator and navigate to C:\Windows\System32\drivers\etc\hosts. Look for the website causing the error and delete that line.
• macOS: In Terminal, type sudo nano /etc/hosts to verify and remove incorrect entries.
If your own website is showing this error to visitors, follow these checks:
1. Verify Domain Registration Check if your domain has expired. If a domain is not renewed, the registry stops resolving it. Use a WHOIS lookup tool to confirm the status is "Active" or "OK". If the status is clientHold, the registrar has suspended the domain, often due to payment issues or unverified contact info.
Check your email for a "WHOIS Verification" request. ICANN (the domain governing body) requires you to verify your contact info. If you ignore this email, your registrar is legally required to suspend your domain, which results in an immediate NXDOMAIN error even if you have paid your bill.
2. Check Your DNS Records Log in to your DNS provider (e.g., Cloudflare, GoDaddy, or your hosting panel). Ensure you have a valid A Record pointing to your server's IP address. If you use a subdomain (like www), ensure there is a CNAME record or A record for it.
Many owners forget the "www" record. If you have an A record for "example.com" but not for "www.example.com," visitors typing the "www" version will see an NXDOMAIN error. Always ensure both (or a wildcard record) are present.
3. Test for Propagation If you recently updated nameservers, the changes might not be visible everywhere yet. Use a global propagation checker tool (like whatsmydns.net) to see if the world sees your new IP or the old one.
4. Check for DNSSEC Issues If you enabled DNSSEC (a security feature), a misconfiguration can cause the domain to fail validation, resulting in a specific type of NXDOMAIN or SERVFAIL error. You may need to disable DNSSEC at your registrar to restore access.
Misconfigured DNSSEC is a common cause of NXDOMAIN errors that are difficult to diagnose. If you recently switched DNS providers (e.g., moving to Cloudflare) but didn't update the "DS records" at your registrar, your domain will appear "Non-Existent" to any DNS resolver that performs security checks.
DNS Resolver A server (usually provided by your ISP) that acts as an intermediary, looking up domain names for your computer.
IP Address The unique string of numbers (e.g., 192.168.1.1) that identifies a server on the internet.
TTL (Time To Live) A setting that tells computers how long to store (cache) DNS information. High TTL values can cause delays when you update your site.
If you see an NXDOMAIN error after making a change, check your TTL. If it's set to 86400 (24 hours), it means the "Non-Existent" result is being saved by servers for a full day before they will try to look it up again.
Propagation The time it takes for DNS changes to spread across the internet, typically taking 24 to 48 hours.
Hosts File A text file on your computer that maps hostnames to IP addresses manually, overriding the public DNS system.
The NXDOMAIN error means a domain cannot be found.
For visitors, the fix is usually to flush the DNS cache or change DNS servers to Google or Cloudflare.
For website owners, the issue is likely an expired domain, DNS propagation delays, or missing A records.
Stability online depends on careful coordination.