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Fix Windows Defender Sync Issues with Microsoft Account - Troubleshoot ERR_TUNNEL_CONNECTION_FAILED in Chrome-How to Fix Windows Update Connection Refused by Proxy

2026-06-13 18:51:13developer-tools
Fix Windows Defender Sync Issues with Microsoft Account - Troubleshoot ERR_TUNNEL_CONNECTION_FAILED in Chrome-How to Fix Windows Update Connection Refused by Proxy

Final checklist

  • Confirm that the same symptom is gone after a restart or refresh.
  • Keep the smallest working change and undo temporary diagnostic settings.