Fix Cloudflare 521 Error Due to Server Overload - Fix Frozen Windows 11 Update Assistant-How to Solve DNS Probe Finished NXDOMAIN from Antivirus
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.