DNS_PROBE_FINISHED_BAD_CONFIG: Causes and Step-by-Step Fixes
DNS_PROBE_FINISHED_BAD_CONFIG indicates that the browser encountered a DNS-related configuration problem. It is commonly associated with invalid resolver settings, corrupted network configuration, VPN or proxy conflicts, or a router DNS problem.
Unlike NXDOMAIN, the error does not necessarily mean the domain is missing. The same site may work correctly from another device or network.
Verify whether the domain itself has valid DNS records.
Quick Fixes for BAD_CONFIG
Start with low-risk steps: restart the browser and device, reconnect the network, flush DNS and verify that DNS settings are automatic or correctly entered. Then investigate VPN, proxy, firewall and router configuration.
Step-by-Step Process
- Restart the browser and computer.
- Restart the modem and router.
- Flush the DNS cache.
- Renew the DHCP lease.
- Reset Winsock and TCP/IP on Windows.
- Disable VPN or proxy temporarily.
- Test a reputable public resolver.
Important Concepts
DHCP
Automatically supplies IP, gateway and DNS settings.
Manual DNS
A mistyped resolver address can break all lookups.
Winsock
Corrupted Windows socket configuration can disrupt networking.
Router relay
A router may advertise itself as DNS while failing to forward queries.
Common Problems and Mistakes
- Invalid preferred DNS address
- Incorrect static IP settings
- VPN adapter left active
- Proxy misconfiguration
- Security software interception
- Router DHCP assigning old DNS values
Troubleshooting Checklist
- Check another website.
- Check another device.
- Review ipconfig /all.
- Return DNS to automatic temporarily.
- Run nslookup against a public resolver.
- Check the domain externally.
Frequently Asked Questions
Is BAD_CONFIG caused by the website?
It is often local, but authoritative DNS should still be checked if only one domain fails.
Should I reset the entire network immediately?
No. Network reset should generally be a later step because it removes and recreates adapters and settings.
Can a VPN cause this error?
Yes. A VPN may assign DNS servers or routes that remain unusable after a failed disconnect.
Conclusion
DNS_PROBE_FINISHED_BAD_CONFIG is an important topic for anyone managing websites, networks or online services. Use the diagnostic steps above to separate local-device, resolver, authoritative DNS and application problems.