DNS_PROBE_FINISHED_BAD_CONFIG: What It Means and How to Fix It

What DNS_PROBE_FINISHED_BAD_CONFIG actually means

Chrome's DNS probe classified the failure as a bad configuration — it couldn't form a valid DNS query at all, not just a failed one. The most common culprits are: a static DNS server that is no longer reachable, leftover DNS settings from a disconnected VPN, a corrupted Windows network adapter, or a manual IP configuration with an incorrect gateway or DNS entry.

Most likely causes (ranked)

1. VPN software crashed or disconnected and left incorrect DNS settings
2. DNS server set manually to an address that is now wrong or unreachable
3. Corrupted Windows TCP/IP or Winsock stack
4. Static IP configuration with wrong subnet mask or gateway
5. Third-party firewall or security software blocking DNS traffic

How to fix DNS_PROBE_FINISHED_BAD_CONFIG

Step 1: Flush DNS cache and renew IP

Windows (Command Prompt as admin):

ipconfig /flushdns
ipconfig /release
ipconfig /renew

macOS (Terminal):

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

Step 2: Set DNS to automatic (DHCP)

Windows: Network Connections → right-click adapter → Properties → IPv4 → select "Obtain DNS server address automatically".
macOS: System Settings → Network → your connection → Details → DNS → remove all manual entries → apply.

Step 3: Try a manual DNS server temporarily

Set DNS to 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google). If this resolves browsing, your ISP's assigned DNS was unreachable. You can keep using a public DNS or wait for your ISP's DNS to recover.

Step 4: Reset TCP/IP and Winsock (Windows)

Open Command Prompt as admin and run:

netsh int ip reset
netsh winsock reset

Restart the computer. This repairs corrupted network stack settings.

Step 5: Disable VPN and proxy software

Completely exit any VPN client (not just disconnect — fully quit the application). If the error clears, the VPN's DNS override is the cause. Reinstalling or updating the VPN client typically resolves recurring occurrences.

Still not fixed? Check your connection

Run a speed test. If download, upload, and ping return results, your internet is functional but DNS is still broken — focus on the DNS steps above. If the speed test also fails, the problem is at the network layer — check router and modem connectivity.

Frequently Asked Questions

What is the difference between BAD_CONFIG and NO_INTERNET?

BAD_CONFIG: DNS settings are invalid — Chrome can't even attempt a DNS query. NO_INTERNET: DNS query was sent but failed — no internet connectivity. BAD_CONFIG is a local configuration problem; NO_INTERNET is a connectivity problem.

Why did this appear suddenly?

Common triggers: a VPN crash leaving bad DNS, a Windows Update that reset network settings, a manually set DNS that is now unreachable, or a router reboot. Flushing DNS and setting DNS to automatic resolves most sudden occurrences.