ReadyNas RN212 Powers Up but Not Responsive or Accessible

I have a ReadyNas RN212 that suddenly became inaccessible on the network.  None of the computers on the network can "see" the ReadyNas.  I attempted to shut down gracefully and reboot, but was unable to get the unit to power down via the Power Button, so was forced to disconnect the power, waited 30 seconds and reconnected.  The unit powers up, the power light is on, both disk activity lights are on, and the backup light is on, but still unable to "see" the ReadyNas on the network.  Thinking it might be a network issue, I powered the unit down again, disconnected the unit from the network and connected it directly to my laptop via Ethernet cable, and powered it back up.  Same thing happens -- the unit powers up, all 4 lights are lit, but my computer can't see the unit.  I have run the ReadyCloud Discovery application, and it too is unable to find the unit.  My ReadyCloud account shows the unit is offline.  I have WD Red 3TB drives in the unit.  I have pulled both drives and used a SATA to USB cable to connect them directly to my laptop which is running Windows 10.  The drives do not show up in File Explorer, but they do show up in Disk Management and appear to be operating correctly.  I have also tried to perform a reset of the unit using the Reset button on the back of the unit, but am unable to get the unit to enter the Boot Menu.  Anytime power is supplied to the unit, it powers up in exactly the same manner with all 4 lights on the front panel lit, but is not responsive to the Power button, the Backup button, or the Reset button.

The unit is plugged into a very good surge protector that also protects my television, cable modem, and other home electronics.  I don't use the unit everyday -- it stores backups of my laptops as well as acts as a media server for 10,000+ photos.  I noticed the problem several days after we had a very short/quick power outage -- the power dropped for less than a second and then came right back on line.  The only reason I noticed the power blip is that the television and cable model rebooted -- none of the digital clocks in the house reset.  I don't know if the ReadyNas issue is related to the power blip, but that seems to be a likely culprit.

Any suggestions on additional diagnostics or corrective actions to get the unit back online?   I have additional back ups of all the data, so I am not concerned about data loss, but I would prefer to not replace the unit if I don't have to.