Quick answer: Flush your DNS cache and check the URL for a typo—if that doesn't work, switch your DNS server to 8.8.8.8 and 8.8.4.4 in your network adapter settings.
What's actually happening here is that your computer asked the configured DNS server to resolve a domain name, and the server replied with a definitive "this domain doesn't exist" response (NXDOMAIN). The NXDOMAIN status is a hard no—it's not a timeout or a temporary failure. That distinction matters, because it means the problem isn't usually a flaky connection; it's either a typo, a stale DNS cache, or a DNS server that's giving you bad answers.
You'll typically see this when you click a link that's been truncated, when a site was taken down, or when your router's DNS cache has poisoned entries. Let's fix it.
1. Check the URL for typos
I know this sounds dumb, but it's the most common cause. Look at the domain carefully. Is it example.cmo instead of example.com? Or maybe the link you clicked has a line break that splits the domain. If you're copying from an email or a PDF, paste it into Notepad first to see the full URL.
2. Flush the DNS cache
Your computer keeps a local cache of DNS lookups. If that cache has a stale NXDOMAIN entry, every request fails instantly even if the site is back up. Flushing clears that.
ipconfig /flushdnsOpen Command Prompt as Administrator and run that. You'll see "Successfully flushed the DNS Resolver Cache." Now try the site again. If you're on Windows 11, that's the same command. If you're on macOS, use sudo dscacheutil -flushcache.
3. Try a different browser or incognito mode
Browsers have their own DNS caches (Chrome especially). Open an incognito window or try Firefox. If it works there, it's a browser cache issue, not a system one. In Chrome, you can also go to chrome://net-internals/#dns and hit "Clear host cache."
4. Switch to a public DNS server
If flushing didn't help, your ISP's DNS server might be returning bogus results. That's not paranoia—ISPs sometimes have outages or misconfigured servers. Switching to Google or Cloudflare DNS usually fixes it.
- Press
Win + Ito open Settings. - Go to Network & Internet > Wi-Fi or Ethernet (whichever you're using).
- Click on your connected network.
- Scroll down to DNS server assignment and click Edit.
- Change the dropdown to Manual.
- Turn on IPv4, set Preferred DNS to
8.8.8.8and Alternate to8.8.4.4(or1.1.1.1and1.0.0.1for Cloudflare). - Save and reconnect.
This is the fix that works most often when the issue isn't a typo. The reason it works is that public DNS servers have better uptime and less aggressive caching policies than most ISP servers.
5. Restart your router
Your router also caches DNS entries. If its cache is corrupted, every device on your network gets the same NXDOMAIN. Power cycle the router (unplug for 30 seconds, plug back in). This is a blunt instrument, but it's effective.
6. Disable IPv6 temporarily
Sometimes the issue is that your system is trying IPv6 DNS and failing. If you have IPv6 enabled, but your router's IPv6 DNS isn't working, you get NXDOMAIN. Disabling IPv6 on your adapter forces IPv4 DNS.
- Open Control Panel > Network and Sharing Center > Change adapter settings.
- Right-click your active adapter and select Properties.
- Uncheck Internet Protocol Version 6 (TCP/IPv6).
- Click OK and restart the adapter (disable and re-enable it).
This isn't a long-term fix—IPv6 is fine in general—but it's a good diagnostic step. If the site loads after this, you know IPv6 DNS is the culprit, and you can fix your router's IPv6 settings instead.
7. Check the hosts file
Rare, but possible. A leftover entry in C:\Windows\System32\drivers\etc\hosts can map a domain to a non-existent IP, and Windows will use that over DNS. Open the file in Notepad as Administrator and look for any lines that aren't commented out (don't start with #). If you see your problem domain there, delete that line and save.
Alternative fixes if none of that works
- Clear browser data—sometimes a corrupted cookie or site data causes this (rare, but happens). Go to browser settings and clear cached images and files.
- Run the network troubleshooter: Settings > System > Troubleshoot > Other troubleshooters > Network Adapter. It's a long shot, but it might catch something I haven't mentioned.
- Update your network adapter driver—a buggy driver can cause all sorts of weird DNS behavior. Go to Device Manager, right-click your adapter, and select "Update driver."
Prevention
The easiest way to avoid this mess is to switch to a public DNS server permanently. It doesn't require any special tools, and you'll get faster, more reliable resolution. Also, if you're a developer or someone who changes DNS often, learn to use ipconfig /flushdns as muscle memory—it solves a surprising number of "the internet is broken" moments that aren't actually broken.
One more thing: if you're using a VPN, disconnect it and test again. Some VPNs intercept DNS queries and can return NXDOMAIN for domains their DNS servers don't know. That's a common trigger I didn't see until after step 6.