I have a similar problem but my Live Book doesn’t show up under the HOME tab. Just the computer I am working on at the time. I can access the MLB on the network, open files on it, etc…but cannot BACKUP.
When I enter type http://mybooklive/UI into the browser I get the sign in page asking for my password. I can open and work with the MBL but cannot get the BACKUP tab to work. The only thing showing is the computer. The MLB doesn’t show up.