After download we try to install the Manager but there is a message that the certificate had been blocked by the owner.
The certificate has been blocked BY YOU (or whoever is the "owner" of the computer, which is what the message is referring to).
You blocked "the Publisher" (which is "us", Virtuali), in your system, so nothing digitally signed by us will ever run, unless you re-trust us again.
To fix this, go to the Control Panel, under "Internet Options", look for the "Content" tab, there should be a "Publishers" button, that will list the software publishers that you trusted, and another tab with untrusted publishers. If you see "Virtuali s.a.s", remove it from both tabs (especially if it's under untrusted)