I’ve also had this problem since I went from free to premium when the firewall kicked in. If I set the firewall off for the minimum 10 minutes, let the barracuda/ssl vpn agent fire open my connection then enable the firewall I can continue to use the connection. I’m about to try and per the faqs etc try and reconfigure it to actually just work instead of off connect on but saw your email first so thought I should response.
By which I mean, settings/active protection/firewall to off for 10 minutes, use your vpn link to open the connection, then back to active protection firewall on.