How to Fix Nginx 'Upstream Connection Refused' Error - Cloudflare SSL Full vs Flexible: Troubleshooting Mixed Content & Errors-Troubleshooting Docker Nginx 502 Bad Gateway

Updated 2026-07-28 11:37:06windows-fixes
How to Fix Nginx 'Upstream Connection Refused' Error - Cloudflare SSL Full vs Flexible: Troubleshooting Mixed Content & Errors-Troubleshooting Docker Nginx 502 Bad Gateway
Before changing system settings, save your work and note the exact error text so you can compare results after each step.

Extra verification checklist

  • Restart the affected app after changing permissions or configuration files.
  • Test the same workflow in a clean browser profile or a temporary user account.
  • Compare the result on another network if the error may be connection related.