How to Enable Windows Defender in Windows 10 - How to Configure Windows Activation: IT Pro Checklist-Fix 'Command Prompt Returns 404 for Localhost'
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.