Fix DNS_PROBE_FINISHED_NXDOMAIN: The 6 Most Common Causes

The DNS_PROBE_FINISHED_NXDOMAIN error means your browser cannot find the IP address for the domain you entered. The "NXDOMAIN" part stands for "Non-Existent Domain," which tells you the Domain Name System (DNS) searched for the website but returned empty-handed. This error appears across all browsers, though Chrome displays the most recognizable version. In our experience supporting hosting clients, this error stems from six predictable causes, and methodically checking each one resolves the issue in under ten minutes for most users.

Unlike server-side errors (500, 502, 503), DNS_PROBE_FINISHED_NXDOMAIN originates from the connection between your device and the DNS infrastructure. The website itself might be perfectly functional while you stare at an error page. Understanding where the breakdown occurs helps you fix it faster and prevents unnecessary panic about your server being down.

How DNS resolution works (and fails)

When you type a URL into your browser, a chain reaction begins. Your device asks a DNS resolver for the IP address associated with that domain name. The resolver checks its cache first. If it doesn't have a recent answer, it queries root servers, then TLD servers, then the domain's authoritative nameservers. When any link in this chain breaks or returns "this domain doesn't exist," you see DNS_PROBE_FINISHED_NXDOMAIN.

The error can originate from your local machine, your router, your ISP's DNS servers, or the domain's actual DNS configuration. Pinpointing which layer failed determines whether you can fix it yourself in seconds or need to wait for someone else to correct a server-side problem.

Cause 1: Corrupted local DNS cache

Your operating system stores DNS lookups in a local cache to speed up repeat visits. When this cache becomes corrupted or contains stale entries, your computer may insist a domain doesn't exist even though the rest of the internet can reach it perfectly fine. This is the single most common cause we encounter when clients report NXDOMAIN errors on specific sites that work for everyone else.

Flushing the DNS cache forces your system to perform fresh lookups. The process differs by operating system:

Windows

Open Command Prompt as Administrator and run:

ipconfig /flushdns

You should see "Successfully flushed the DNS Resolver Cache." For a more thorough reset, also release and renew your IP address:

ipconfig /release
ipconfig /renew

macOS

Open Terminal and run the command appropriate for your macOS version. For Ventura and later:

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Linux

The command depends on your DNS service. For systems using systemd-resolved:

sudo systemctl restart systemd-resolved

After flushing, restart your browser completely (close all windows, not just the tab) and try accessing the site again.

Cause 2: Browser DNS cache (separate from system cache)

Chrome, Firefox, and other modern browsers maintain their own internal DNS cache independent of your operating system. Even after flushing the system cache, your browser might serve stale data from its private store. This explains why a site loads in Firefox but fails in Chrome, or vice versa.

For Chrome, type the following into the address bar:

chrome://net-internals/#dns

Click "Clear host cache" to flush Chrome's internal DNS records. While you're there, navigate to the "Sockets" section in the left menu and click "Flush socket pools" to clear any persistent connections that might be causing issues.

If you've modified any experimental features, reset them by visiting:

chrome://flags

Click "Reset all to default" at the top of the page. Some experimental DNS or networking flags can interfere with normal resolution.

Cause 3: Misconfigured or failing DNS servers

By default, your device uses DNS servers assigned by your router, which typically inherits them from your ISP. ISP DNS servers are notorious for poor performance, intermittent outages, and aggressive caching that ignores TTL values. When your ISP's DNS infrastructure experiences problems, every domain lookup fails or returns incorrect results.

Switching to a reliable public DNS provider often resolves NXDOMAIN errors immediately. The two most popular options are Google Public DNS (8.8.8.8 and 8.8.4.4) and Cloudflare DNS (1.1.1.1 and 1.0.0.1). Both offer faster response times and better uptime than most ISP resolvers.

Changing DNS on Windows

Open Control Panel, navigate to Network and Sharing Center, and click on your active connection. Select Properties, then highlight "Internet Protocol Version 4 (TCP/IPv4)" and click Properties. Select "Use the following DNS server addresses" and enter:

• Preferred DNS server: 8.8.8.8
• Alternate DNS server: 8.8.4.4

Click OK, close all windows, and restart your browser.

Changing DNS on macOS

Open System Preferences (or System Settings on newer versions), click Network, select your active connection, and click Advanced. Navigate to the DNS tab, click the plus (+) icon, and add 8.8.8.8 and 8.8.4.4. Click OK, then Apply.

Changing DNS on Linux

Edit your resolv.conf file temporarily or configure your network manager permanently. For a quick test:

sudo nano /etc/resolv.conf

Add or modify the nameserver lines:

nameserver 8.8.8.8
nameserver 8.8.4.4

Note that this change may be overwritten on reboot depending on your network configuration. For permanent changes, configure DNS through NetworkManager or your distribution's network settings.

Cause 4: Local hosts file blocking the domain

The hosts file on your computer acts as a local DNS override. Before your system queries any external DNS server, it checks this file first. Malware, overzealous security software, or forgotten manual entries can redirect domains to invalid addresses (like 0.0.0.0 or 127.0.0.1), causing NXDOMAIN-like behavior.

We regularly encounter this when clients install ad-blocking or parental control software that modifies the hosts file aggressively. Uninstalling the software doesn't always clean up the hosts file entries.

Checking the hosts file on Windows

Navigate to C:\Windows\System32\drivers\etc\ and open the "hosts" file with Notepad (run as Administrator). Look for any lines containing the domain you're trying to reach. If you find entries pointing the domain to 127.0.0.1, 0.0.0.0, or any IP that isn't the legitimate server, delete those lines and save the file.

Checking the hosts file on macOS and Linux

Open Terminal and run:

sudo nano /etc/hosts

Review the file for suspicious entries. A clean hosts file typically contains only localhost definitions (127.0.0.1 localhost). Remove any lines that redirect the problematic domain. Save with Ctrl+O and exit with Ctrl+X.

Cause 5: VPN or security software interference

VPN applications route your traffic through their own DNS servers to prevent DNS leaks that could expose your browsing activity. When VPN software malfunctions, fails to connect properly, or conflicts with your system's network stack, DNS resolution breaks entirely. The VPN intercepts your DNS queries but fails to forward them correctly, resulting in NXDOMAIN errors.

Antivirus and firewall software can cause similar issues. These applications often include "web protection" features that inspect DNS queries and block connections to domains they consider suspicious. False positives occur regularly, especially with new or less popular websites.

To diagnose VPN or security software interference:

• Temporarily disconnect your VPN completely (not just pause it)
• Disable your antivirus software's web protection or real-time scanning temporarily
• If using a corporate firewall or proxy, test from a different network

If the site loads after disabling these tools, you've identified the culprit. Check the software's settings for domain whitelisting options, or contact the vendor about false positive reports.

Cause 6: The domain actually doesn't exist (server-side issues)

Sometimes NXDOMAIN is accurate: the domain genuinely has no DNS records. This happens when domains expire, when DNS zone files are misconfigured, when nameservers are changed without proper record migration, or when the domain was never properly set up in the first place.

If you've exhausted client-side fixes and other users also cannot reach the site, the problem lies with the domain owner's configuration. You can verify this using online tools:

• ICANN Lookup: Check whether the domain is registered and active, or if it has expired
• DNS Checker tools: Query multiple global DNS servers to see if anyone can resolve the domain
• WHOIS lookup: Verify the domain's registration status and nameserver configuration

If you own the domain experiencing NXDOMAIN errors, verify these configurations:

• Confirm your domain hasn't expired at your registrar
• Check that nameservers at your registrar point to the correct DNS provider
• Verify A records (and AAAA for IPv6) exist for both the apex domain (example.com) and www subdomain
• If you recently changed nameservers, allow up to 48 hours for propagation

When managing domains through ServerSpan, our support team can verify DNS configuration and identify misconfigured records within minutes. Common issues we resolve include missing A records after migrations, incorrect nameserver delegation at registrars, and DNSSEC mismatches that cause validation failures.

The diagnostic sequence: fastest path to resolution

When you encounter DNS_PROBE_FINISHED_NXDOMAIN, work through these steps in order. Each step takes under two minutes and rules out one potential cause:

1. Try a different browser or device: If Chrome fails but Firefox works, focus on browser-specific fixes. If your phone works but your laptop doesn't, focus on laptop-specific fixes.
2. Open an incognito/private window: This bypasses most browser caching and disables extensions that might interfere.
3. Flush system DNS cache: Takes 10 seconds and resolves the most common cause.
4. Try a different DNS server: Temporarily switch to 8.8.8.8 to rule out ISP DNS issues.
5. Check your hosts file: Look for entries blocking the specific domain.
6. Disable VPN and security software: Test without these layers intercepting your traffic.
7. Test from a different network: Use mobile data instead of WiFi to bypass your entire local network stack.
8. Check if the domain exists: Use online tools to verify the domain's DNS records are properly configured.

This sequence moves from fastest fixes to more involved troubleshooting, and from client-side issues (which you can fix) to server-side issues (which require the domain owner's action).

Preventing future NXDOMAIN errors

Once you've resolved the immediate issue, a few configuration changes reduce the likelihood of recurrence:

• Use reliable public DNS permanently: Configure Google (8.8.8.8) or Cloudflare (1.1.1.1) DNS at your router level so all devices benefit
• Keep your system and browser updated: DNS-related bugs get patched in updates
• Review security software settings: Whitelist legitimate domains and disable overly aggressive web filtering
• For domain owners: Set up monitoring alerts for DNS resolution failures and domain expiration warnings

If you're running websites on ServerSpan infrastructure, our managed DNS includes automatic health checks that alert you before DNS misconfigurations cause visitor-facing errors. Catching expired domains or misconfigured records before they trigger NXDOMAIN errors protects your business from preventable downtime.

When NXDOMAIN errors affect your own website

Receiving reports that visitors see DNS_PROBE_FINISHED_NXDOMAIN when accessing your site requires immediate investigation. Unlike client-side issues that affect individual users, server-side DNS problems affect everyone trying to reach you.

Start by querying your domain from multiple locations using a global DNS checker. If the domain fails to resolve worldwide, check your registrar account for expiration warnings or nameserver changes. If DNS resolves correctly in some regions but not others, you're likely experiencing propagation delays from recent changes, which resolve within 24-48 hours.

For sites hosted with professional providers, DNS issues often trace back to the "glue" between the registrar (where you bought the domain) and the hosting provider (where your site lives). Ensure your registrar's nameserver settings point exactly to your host's nameservers, with correct spelling and no trailing periods or spaces. One typo in ns1.serverspan.com becomes an NXDOMAIN error for every visitor.

When you need expert assistance diagnosing complex DNS issues, ServerSpan's managed services include DNS troubleshooting as part of our support scope. We've resolved thousands of NXDOMAIN situations and can often identify the root cause within minutes by checking authoritative nameservers, verifying zone file configurations, and testing resolution from multiple global locations.