AC2400 Router will not add USB for ReadySHARE

I have replaced the USB drive attached to my AC2400 router. I upgraded from a 2TB WD USB drive to a 4TB WD MyBook USB 3.0 drive. The router will not see it and set up readySHARE. When I plug it in, the USB light on the router comes on for about 3-5 seconds, then goes out. When I access the router, it says under the ReadySHARE tab on the BASIC home page 'No USB Drive'. When I go to the ADVANCED>Advanced Setup>USB Settings, I have enabled any USB device, and my drive shows up under the Available USB Devices list (it shows U Drive - My Book 25EE - 3726.0GB). If I select the radio button next to it and click the +Add button, I get a failure that says:This Site Says... Approved Devices! (The Allow Only Approved Devices box at the top is unselected) I have tried all combinations, rebooted the router multiple times, verified most up to date FW (Router Firmware Version V1.2.0.62_1.0.1) For fun I plugged in a USB jump drive, and it shows up immediately and sets up as the ReadySHARE drive. 

Help, please!

Dan