Backupper Network not showing uncontrolled PC

Hi all,

Please can anybody help me?

I had this odd behaviour:

after the installation of the Backupper client on the network PCs, the PCs were visible in Backupper Network/Computers tab and available for control, but after attempting the get the control of the first in the list using username and password, Backupper Network stopped responding and the entire list disappeared and there is no way to get it back.

I tried to uninsitall/reinstall Backupper Network but with no luck, the list is still unavailable.

Any suggestion to solve the problem?
All PCs are are running Windows 10 including the one with Backupper Network.

Thanks

Marco