In almost all cases, there is no more need to configure any port forwarding or other tricks at all, it works right out of the box.
The message you get indicates that there is no connection to the connection server. This connection is almost as simple as when you google in your browser, so there are 4 possibilities:
- the connection server was down. Very unlikely, but you may just try again and see if it works
- you have manipulated either the router or the OS firewall (Mac or PC) such that they block incoming UDP. In their default configuration there should never be a problem.
- you installed another additional firewall application. Disable it and try again.
- your internet connection was broken. Could you google?
Hope that helps.
p.s. this is the wrong forum, you should post to the VST connect forum.