WD My Book and Time Machine

I have a WD My Book 8TB plugged into the USB 3 port on a NightHawk R8000 router. It is formatted in HFS+ journaled with a guid structure. I cannot get Time Machine to see the drive. I can see it in Finder and open it. Has anyone had a similar problem?

Hello,

Please refer to the following KBA article: macOS Time Machine Online User Guide and Solutions