Troubleshooting "ERR_NAME_NOT_RESOLVED"

The `ERR_NAME_NOT_RESOLVED` error (often appearing as "This webpage is not available" or "This site can’t be reached") signals that your browser was unable to find the IP address corresponding to the domain name you entered. It's fundamentally a Domain Name System (DNS) lookup failure.

What It Means: DNS Failure

Think of DNS as the internet's phonebook. When you type `google.com`, your browser asks a DNS server for the numerical IP address of Google's server. If the DNS server can't find or provide that IP address, your browser doesn't know where to send the request, resulting in this error.

Common Causes

  • Typo in the Domain Name: Simply misspelling the website address is a frequent cause.
  • DNS Server Issues: The DNS server your computer or network is configured to use might be down, unresponsive, or experiencing problems.
  • Local DNS Cache Corruption: Your operating system or browser might have stored incorrect or outdated DNS information.
  • Router/Modem Problems: Your home network equipment might be malfunctioning or have incorrect DNS settings.
  • Firewall or Antivirus Blocking: Security software could potentially interfere with DNS lookups.
  • Domain Doesn't Exist or Expired: The domain name itself might be invalid, unregistered, or recently expired.
  • Incorrect Network Configuration: Manual network settings on your device might specify incorrect DNS server addresses.
  • ISP DNS Problems: Occasionally, your Internet Service Provider's DNS servers might experience outages.

Troubleshooting Steps (Mostly Visitor-Side)

This error is usually related to the user's connection, device, or the DNS system itself, rather than the target website's server (unless the domain genuinely doesn't exist).

  1. Check for Typos: Double-check the spelling of the domain name in the address bar.
  2. Clear Browser Cache and Cookies: Remove potentially conflicting stored data.
  3. Flush Local DNS Cache: Force your OS to clear its stored DNS records.
    • Windows: Open Command Prompt as Admin, type `ipconfig /flushdns`, press Enter.
    • macOS: Open Terminal, type `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder`, press Enter.
    • Linux: Often `sudo systemd-resolve --flush-caches` or `sudo /etc/init.d/nscd restart`.
  4. Restart Router and Modem: Power cycle your network equipment to clear temporary glitches.
  5. Change DNS Servers: Configure your device or router to use public DNS servers like Google (8.8.8.8, 8.8.4.4) or Cloudflare (1.1.1.1, 1.0.0.1) instead of your ISP's default servers.
  6. Check Firewall/Antivirus: Temporarily disable them to see if they are interfering with DNS lookups.
  7. Reset TCP/IP Stack (Windows): In Command Prompt (Admin), run:
    netsh winsock reset
    netsh int ip reset
    Then restart your computer.
  8. Check Your Hosts File: Ensure the domain isn't incorrectly mapped to a wrong IP address in your computer's `hosts` file (usually an advanced user issue).
  9. Try a Different Device/Network: See if the website loads on your phone using mobile data or on another computer on a different network. This helps isolate if the problem is specific to your device or network.
  10. Check Domain Existence/Status: Use a WHOIS lookup tool to verify the domain is registered and hasn't expired.

Note for Website Owners

If multiple users report `ERR_NAME_NOT_RESOLVED` for your site, the problem likely lies with your domain's DNS configuration:

  • Check Nameserver Settings: Ensure your domain registrar settings point to the correct nameservers provided by your DNS host (which might be your registrar, hosting provider, or a service like Cloudflare).
  • Verify DNS Records: Confirm that the necessary DNS records (especially the 'A' record pointing to your server's IP address) exist and are correct at your DNS host.
  • Wait for DNS Propagation: If you recently changed nameservers or DNS records, it can take up to 24-48 hours for the changes to propagate globally.