Hello @Ron the Flash and welcome to the Community!
Are you getting this message in Central? "Unable to connect to the server. Sorry, we are unable to connect to the server. Please try again later". Or what is the full message displayed and where exactly?
If yes, restart the computer then try again to sign in. If the installation is done from Bitdefender Central, the product should be activated automatically at the end of the installation process.
Let us know if the issue persists and we shall advise further.
Regards
