Photoshop: Export Artboard to Files Problem

I am using the latest version of Photoshop CC. I have tried a million times to export my artboard as PNG files. It is not working. It exports the entire artboard as one files.

I have tried restarting photoshop

I have uninstalled Photoshop and return to previous versions.

Still, nothing works.

As a result of them, I have not been able to meet my customer's demand for 2 days.

PLEASE HELP.