WD TV Live can't see a network drive

My WD TV Live can’t see my network drive V (only using specifics to make it easier to describe).

Other devices on the network can see it, including a phone with an explorer-type app.

Drive V is an external drive, and so is drive T which is an external drive on the same computer as V - WD TV Live can see T but not V

They appear to be defined identically (famous last words…)

The PC to which the drives are connected is running Windows 10.

I have tried re-booting both the WD TV Live and the PC where drive V lives

I’d recommend double-checking the permissions for the missing unit and comparing them to the hard drive that works. If you mean they do share identical permission settings when you describe them as defined identically, then test if the missing unit works if permissions are deleted and re-added.