Hey there, @TwistedTransistor!
I'd recommend you try to swap the USB cable that is connecting the WD My Passport and see if the Xbox One would recognize it then. If you haven't tried this already, you could also attempt to plug the external using a USB 3.0 Hub. I'd also suggest you go to All Settings > System > Storage > Manage storage in the Xbox one menu and see if the external drive is listed in the storage devices there.
I'd also advise you to check if you have everything up-to-date on the console info & updates as well. Are you able to access the WD My Passport on the Xbox 360 console?
Keep me posted with the troubleshooting!
SuperSoph_WD