Local access to PR4100 lost when internet went down

Our internet went out, and I have a PR4100 for local access only.
I could browse to the device, and I could still watch movies, but my mapped drives would not work (Windows 10).
I could not navigate to the files either using the Windows Explorer navigation bar.
Does anyone know why local access would go away because the internet is down?

All local devices are connected to the same switch as the PR4100. That switch is connected to our Xfinity modem/router.

Thanks

Hi,

This is to inform you that please ensure that the My Cloud drive is configured with a static IP address.

For more information, please refer to this KB article: How To Map a WD Network Drive on Windows 10

It has a static IP address.

The drives were mapped and accessible. When the internet went down, I lost access to the mapped drives, but I could still browse to web page and log in as admin to see everything was fine. I could also still stream movies to my TV. I just could not access the mapped drives. Why would accessing the mapped drives require the internet since everything is on the same switch on the same network?