Can you share the path to the installation directory of the toolbox? And can you tell me if you have installed the toolbox on a shared drive ? Common problems with this are:
wrong disk id in the license
installation paths with spaces
installation on a shared drive - here there is usually some kind of firewall setup that is blocking the licensing system
local firewall
The first one you checked and it is ok, so this is why I'm looking for the other problems.