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Fix Windows Update Invalid Configuration Group Policy Error - Command Prompt Connection Refused: Firewall Troubleshooting-KMS Port 1688 Already Allocated Error Fix

Updated 2026-06-13 20:21:42developer-tools
Fix Windows Update Invalid Configuration Group Policy Error - Command Prompt Connection Refused: Firewall Troubleshooting-KMS Port 1688 Already Allocated Error Fix
Likely symptom
Likely cause
Safe rollback

Verification route

  • Repeat the original action, not only a simplified test case.
  • Restart the app or reload the service after configuration changes.