Can't see Droboshare on the network

I have a 1st gen Drobo with a Droboshare module which has been running smoothly for a number of years. Recently I lost sight of the Droboshare on the network and checked the device and confirmed all status lights were green (including the power and network activity light on the Droboshare).

I’ve tried resetting the Droboshare as described here but this has not helped either. The Droboshare boots up with both lights (power and network activity) solid green. Its been so long I can’t remember if I originally set it up with a static IP or used a DHCP reservation but I thought the reset would do it by resetting it back to using DHCP. My router shows no DHCP allocation based off its mac address.

What are the next steps I should take to troubleshoot this?