Hi , I had similar problems with Cisco Work discovering switches in Panama, I was able to fix it by checking and changing the discovery settings. I change the HOP limit and confrim that all of our subnets were listed in the Filter Settings, is the unit in question reachable from your Seed device? it should be. You can go to Device Center and do a SNMP walk to the IP address of the device if it fails you might consider added it manually. HTH