Your DNS server might be unavailable

How to Fix “Your DNS server might be unavailable”

Windows Network Error 📄 Windows 10, Windows 11

⚡ Quick answer

"Your DNS server might be unavailable" is a Windows Network Diagnostics message shown when the troubleshooter detects that DNS queries aren't working. Your internet connection may be physically working, but domain names can't be resolved.

First, check if your internet is working and what your current IP address is:

🔍 Check My IP Address →

What Causes the “Your DNS server might be unavailable” Error?

Windows Network Diagnostics runs a DNS test and it fails. This happens when: your ISP's DNS server is down, your router isn't forwarding DNS queries properly, your DNS settings point to a non-existent server, Windows's DNS Client service has stopped, or your network adapter driver has a bug affecting DNS.

How to Fix It — 5 Methods

1 Change to a Public DNS Server ▶

This directly fixes the problem if your ISP's DNS is down. Go to Control Panel → Network and Sharing Centre → Change adapter settings → right-click your connection → Properties → Internet Protocol Version 4 → Use the following DNS server addresses:
Preferred: 8.8.8.8
Alternate: 8.8.4.4
Click OK. Open Command Prompt and run ipconfig /flushdns.

2 Restart the DNS Client Service ▶

Press Windows+R → type services.msc → find "DNS Client" → right-click → Restart. If it's stopped, right-click → Start. The DNS Client service caches DNS responses and manages lookups — if it crashes, all DNS fails.

3 Flush DNS Cache ▶

Open Command Prompt as administrator → ipconfig /flushdns. Also run ipconfig /registerdns to re-register DNS. Then restart your browser and test.

4 Restart Your Router ▶

Many home routers act as a DNS relay — they forward your DNS queries to your ISP's servers. If the router's DNS relay is stuck, restarting it fixes the issue. Unplug for 30 seconds, plug back in, wait for full startup.

5 Update or Roll Back Network Adapter Driver ▶

A buggy driver can cause DNS to fail. Open Device Manager → Network Adapters → right-click your adapter → Update driver. If the issue started after a recent Windows Update, try: Properties → Driver → Roll Back Driver to the previous version.

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Some errors are caused by ISP blocks or network restrictions

A VPN bypasses them instantly by routing through a different server.

PureVPN → IPVanish →

✅ Fixed it? Visit tools.examineip.com to confirm your IP address and connection are working correctly.

Frequently Asked Questions

Windows troubleshooter says "fixed" but the problem persists — why?

The troubleshooter sometimes resets DNS to defaults temporarily (fixing it for the test) but doesn't address the root cause. Manually set your DNS to 8.8.8.8 / 8.8.4.4 as a permanent fix rather than relying on the troubleshooter.

Websites load but the troubleshooter still says DNS might be unavailable — is something wrong?

If sites actually load, your DNS is working. The troubleshooter may be running its DNS test against a specific server that's blocked or slow, even though your actual DNS resolves fine. You can ignore this message if everything is functioning normally.

Can antivirus software cause this error?

Yes. Antivirus programs with network protection can intercept or block DNS queries. If the error appeared after installing antivirus software, temporarily disable its network/DNS protection feature and test.

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Last updated: April 2, 2026 • Report an error