Volumio Doesn't Detect Music on Portable HD

I am using an Allo Digione Player feeding SPDIF into a Schiit Modi3 and using Volumio 2.502. I have FLAC files loaded on a Western Digital Passport 1 TB HD plugged into the Digione through one of it’s USB ports. My problem is that no music is detected by volumio. Do I have to manually load a drive since the Passport is plugged directly to the Digione? If so, do I use the Digione’s IP address for the HD? Any help is greatly appreciated!