WD My Book Essential 3TB USB 3.0 and NV+ v2

I naively bought a WD My Book Essential 3TB USB 3.0 (USB 2.0 compatible) for use as a backup drive for my NV+ v2 (with 3 x 3TB WD drives inside), having used a number of different USB 2.0 drives in the past successfully (2 x Samsung 1.5TB Story Stations, Buffalo 2.0 TB Just Store Desktop). Unfortunately the NV+ refuses to recognise the WD drive, either in the USB 3.0 ports or the front USB 2.0 port. The WD is formatted as NTFS, as were the other drives I have used.

I am currently using the WD drive as a backup via my iMac (connected using Gigabit Ethernet to the NAS), but it would be more convenient to use it directly with the NAS.

Has anyone successfully used this mainstream drive with an NV+ v2? Has anyone got any suggestions?