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Fix Windows Defender Proxy Error Sync Issue - Fixing Microsoft Teams Authentication Failed for Guest Users-Windows Security Certificate Error Connection Refused Fix

2026-06-17 11:38:36windows-fixes
Fix Windows Defender Proxy Error Sync Issue - Fixing Microsoft Teams Authentication Failed for Guest Users-Windows Security Certificate Error Connection Refused Fix

Final checklist

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