I get "Invalid key" error message when try to register vertical drop down css3 menu

Q: I have bought CSS3Menu recently, but have problems with registration. I can't get the registration key to work. It keeps telling me it is invalid.
What can I do?

A: It seems that your antivirus/firewall/proxy doesn't allow Internet connection for CSS3Menu. So you get "Invalid key" error message.
Please contact with customer support at support [at] visuallightbox [dot] com for further instructions.