An "EnumDisplayDevicesA() failed" error when running 3DMark suggests that Windows 10 cannot properly identify your monitors or that a third-party application has modified how they are set up.
- To fix this issue, open Windows Device Manager.
- Expand the Monitors section, and find your monitor(s) in the list of devices.
- Right-click and choose "uninstall device" for each monitor.
- Open the Action menu and choose Scan for hardware changes to detect your monitor(s). They will reappear in the list.
- Restart 3DMark, and run the test again.