How to Fix Cloudflare 521 Error with Wildcard Subdomains - Git Error: Index Lock File Exists – How to Fix-Fix ERR_NAME_NOT_RESOLVED on All Sites in Chrome
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.