Windows Defender 502 Bad Gateway: Troubleshooting Checklist
If you see a 502 Bad Gateway error when opening Windows Security or trying to update Windows Defe...
Checklists for software errors, setup, and tool workflows.
1. Reproduce
2. Isolate
3. Apply
4. Verify
Latest checklists
View listFix Windows Security High Memory Usage
You open Task Manager and see Windows Security (or Antimalware Service Executable) using 500 MB o...
Fix Windows Update Connection Refused with Netsh Winsock Reset
If Windows Update shows a "connection refused" error, it often points to a corrupted Winsock (Win...
Fix Windows Security Connection Timeout Error
When you see a 'connection timeout' error in Windows Security, it usually means the app can't rea...
Fix Windows Activation Blocked by Proxy Server
If Windows activation fails with an error like “We can’t activate Windows on this device because ...
Fix 'Windows Update Auto Start Service Not Found' Error
You may see a message that the Windows Update auto-start service is not found, often when trying ...
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Windows Defender Setup Error 504 TroubleshootingHow to Resolve 'Permission Denied' on WindowsHow to Fix Windows Update Service Not StartingFix Windows Security Permissions Loading ErrorHow to Configure Proxy Settings for Windows DefenderWindows Security Network Error After Update – TroubleshootingFix Windows Update Server Refused Connection ErrorsWindows 11 Defender DNS Error Troubleshooting Guide