Fix DNS Probe Finished NXDOMAIN Caused by Antivirus Blocking - Fix Nginx 'upstream connection refused' When Talking to PHP-FPM-Fix Cloudflare 526 Origin Certificate Error

Updated 2026-07-28 14:24:39cloud-software
Fix DNS Probe Finished NXDOMAIN Caused by Antivirus Blocking - Fix Nginx 'upstream connection refused' When Talking to PHP-FPM-Fix Cloudflare 526 Origin Certificate Error
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.