How to Resolve Cloudflare Origin Certificate Chain Issues
When Cloudflare's edge cannot validate your origin server's certificate chain, visitors m...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listFix DNS Probe Finished NXDOMAIN on Google DNS Setup
If you see "DNS probe finished NXDOMAIN" in your browser, it means your device couldn'...
Fix Nginx Configuration Test Failure for Upstream Directive
When you run nginx -t and get an error involving the upstream directive...
Windows Security App Not Working After Reset? Try These Fixes
If you recently reset your Windows PC and now the Windows Security app won't open, shows a bl...
Fix NET::ERR_CERT_AUTHORITY_INVALID on Windows 10
You're browsing in Chrome or Edge and see NET::ERR_CERT_AUTHORITY_INVALID. T...
Fix Explorer.exe Keeps Restarting in Windows 10
If your File Explorer (explorer.exe) keeps restarting on Windows 10, you'll see the taskbar a...
Topic paths
Quick titles
Troubleshooting Cloudflare DNS Not Updating After SSL UpdateResolve Git Remote Origin Already ExistsNvidia Chrome Black Screen: Hardware Acceleration TroubleshootingWindows 11 WiFi Connected But No Internet After UpdateNginx Configuration Test Failed: Duplicate Listen FixFix DNS Probe Finished NXDOMAIN After Windows UpdateHow to Clear Edge Sync Cache and Resolve Sync IssuesDocker Container Exits Immediately: Fix with Restart Policy