Fix Cloudflare 525 Error After SSL Certificate Update - Windows Defender Proxy Issue Troubleshooting-Troubleshooting Windows Defender Virus Definition Updates

Updated 2026-06-13 13:40:17windows-fixes
Fix Cloudflare 525 Error After SSL Certificate Update - Windows Defender Proxy Issue Troubleshooting-Troubleshooting Windows Defender Virus Definition Updates
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.