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Fixing Nginx Upstream Connection Refused on Port 443 - Cloudflare 521 Error: How to Fix Server Timeout-Fix: Real-Time Protection Turns Off by Itself in Windows Defender

2026-07-28 05:47:48
Fixing Nginx Upstream Connection Refused on Port 443 - Cloudflare 521 Error: How to Fix Server Timeout-Fix: Real-Time Protection Turns Off by Itself in Windows Defender

Result check

  • Keep one change per test run so you know which step helped.
  • Undo temporary changes after the issue is confirmed.

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