RBK753 router keeps losing Internet connection, shows magenta ring

There aren't any problems with the Internet connection, it's the RBR that's the issue.  I have a home-run RG6 line running from outside straight to the cable modem with no splitters installed, and my ISP has confirmed no service problems.  Additionally, the second time this happened, I took the Ethernet cable (the one that came with the Orbi packaging) out of the RBR WAN port and plugged it directly into my computer's hub and connected easily to the Internet via hardline, so the line leading to the RBR was still active.  I've placed it 4 feet away from other devices, but there seems to be something going on with the RBR that's causing it to suddenly decide it doesn't want to be connected to the Internet anymore.