It wouldn't be DNS settings. I don't have a network drive/media server connected so don't know exactly how it shows up
That link I posted is to enable Media Server/sharing on an Asus drive not Android. Once you plug a drive in an enable network sharing through the settings for the device, you then point your Media player to that through the individual settings on the App or media program that you're using.
If you have one connected, it should pick it up in a scan or you may have to map it manually
I install FTTP for Openreach. BT Business Customers get a 4G Dongle with their Service that is permanently plugged into the Smart Hub USB Port so if the Fibre Link goes down the 4G kicks in immediately and there’s no loss of service.