Fix Microsoft Store App 404 Error on Windows 10 - How to Resolve Expired Security Token in Windows-Microsoft Store 504 Error: Causes and Solutions
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.