DNS Server Unavailable: What It Means and How to Fix It

When you see the message “DNS server unavailable”, it means that your device is unable to communicate with the DNS (Domain Name System) server, which is responsible for translating domain names (like example.com) into IP addresses that computers use to locate websites. This error prevents you from accessing websites because your device can’t resolve domain names into IP addresses.

In this article, we’ll explain what the DNS server unavailable error means, its common causes, and how to troubleshoot and resolve the issue.

What Does “DNS Server Unavailable” Mean?

The DNS (Domain Name System) is like the phonebook of the internet, translating user-friendly domain names into machine-readable IP addresses. When the DNS server is unavailable, your device cannot resolve domain names, which leads to errors when you try to access websites.

This issue can occur due to various reasons, including network configuration problems, issues with your internet service provider (ISP), or problems with your device.

Common Causes of the DNS Server Unavailable Error

Several factors can contribute to the DNS server unavailable error:

1. DNS Server Outage

The DNS server provided by your ISP might be down or experiencing heavy traffic, making it temporarily unavailable.

2. Network Configuration Issues

Incorrect network settings on your computer or router could prevent your device from connecting to a DNS server.

3. Firewall or Antivirus Interference

Sometimes, security software (firewalls or antivirus programs) can block DNS requests, causing connection problems.

4. Router or Modem Issues

Problems with your router or modem, such as outdated firmware or incorrect DNS settings, can disrupt the connection to the DNS server.

5. Incorrect DNS Settings

Manually configured DNS settings on your computer or router might be pointing to the wrong DNS server.

How to Fix the DNS Server Unavailable Error

Here are several methods you can try to resolve the DNS server unavailable error:

1. Restart Your Router and Modem

The simplest solution is often the most effective. Restarting your router and modem can refresh your internet connection and resolve any temporary issues.

Steps:

1. Turn off your modem and router by unplugging them from the power source.
2. Wait 30 seconds, then plug them back in.
3. Wait for the devices to fully reboot, and check if the issue is resolved.

2. Flush DNS Cache

Your computer stores IP addresses of websites in a DNS cache to speed up access. Sometimes, this cache can become corrupted, leading to DNS issues. Flushing the DNS cache can help resolve this.

Steps (Windows):

1. Press Windows + R, type cmd, and press Enter to open the Command Prompt.
2. In the Command Prompt, type the following command and press Enter:
   ipconfig /flushdns
3. Once completed, restart your browser and try accessing the website again.

Steps (macOS):

1. Open the Terminal (press Command + Space and type Terminal).
2. In the terminal, type the following command and press Enter:
   sudo killall -HUP mDNSResponder
3. Enter your password if prompted, then try reconnecting.

3. Change DNS Server Settings

If the DNS server provided by your ISP is causing the problem, you can manually change your DNS server settings to use a reliable public DNS service like Google DNS or Cloudflare DNS.

Steps (Windows):

1. Open the Control Panel and go to Network and Sharing Center.
2. Click on Change adapter settings on the left side.
3. Right-click on your active internet connection and select Properties.
4. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
5. Choose Use the following DNS server addresses and enter the following:
   • Preferred DNS server: 8.8.8.8 (Google DNS) or 1.1.1.1 (Cloudflare DNS)
   • Alternate DNS server: 8.8.4.4 (Google DNS) or 1.0.0.1 (Cloudflare DNS)
6. Click OK to save the changes.

Steps (macOS):

1. Go to System Preferences > Network.
2. Select your active network connection and click Advanced.
3. Go to the DNS tab.
4. Click the + button and add the following DNS servers:
   • 8.8.8.8 (Google DNS) or 1.1.1.1 (Cloudflare DNS)
   • 8.8.4.4 (Google DNS) or 1.0.0.1 (Cloudflare DNS)
5. Click OK and then Apply to save the settings.

4. Disable Antivirus or Firewall Temporarily

Sometimes, your antivirus or firewall settings may interfere with DNS connections. Temporarily disabling these programs can help you identify if they are causing the issue.

Steps (Windows Defender Firewall):

1. Open the Control Panel and go to System and Security.
2. Select Windows Defender Firewall.
3. Click Turn Windows Defender Firewall on or off.
4. Select Turn off Windows Defender Firewall (for both private and public networks) and click OK.
5. Test your internet connection. If it works, you may need to adjust your firewall settings to allow DNS traffic.

After testing, make sure to enable your antivirus or firewall again for security.

5. Reset TCP/IP Stack

Resetting the TCP/IP stack can resolve network-related issues, including DNS errors.

Steps (Windows):

1. Open the Command Prompt as an administrator (press Windows + X, then select Command Prompt (Admin)).
2. Type the following commands one by one, pressing Enter after each:
   netsh int ip reset netsh winsock reset
3. Restart your computer and check if the DNS issue is resolved.

6. Contact Your Internet Service Provider (ISP)

If none of the above methods work, the problem may lie with your ISP’s DNS server. Contact your ISP to inquire about possible DNS server outages or issues. They may also provide alternative DNS servers or help you troubleshoot the problem.

Conclusion

The DNS server unavailable error can prevent you from accessing websites and other online services, but it’s usually easy to fix. By following the steps outlined in this guide—restarting your router, flushing the DNS cache, changing DNS servers, or resetting network settings—you can resolve the issue and get back online. If the problem persists, contacting your ISP for assistance is the next best step.