Are you the owner of the computer? I can't really explain this, but the administrator (the person who set up the computer and who the computer is licensed to) can choose to set up another person onto their computer, but that extra person cannot access the administrators stuff. If this makes sense, get the owner of the computer to unblock it for you as you need thier permission to use it.

If this doesn't help, then check your defender and firewall to make sure they are not blocking it. I have no idea otherwise....