I installed Avast free and everything was fine but on Valentine’s Day was a discount so I bought a license. Purchase successful but the problem is that when I go to the tab that pops up account avast can not connect to the internet and so I can not use a purchased license. Please, quick help I do not want to waste the money spent. 
What os/sp ?
What exact version of avast ?
Did you remove any prior installed av before installing avast ?
Already done a repair of avast ?
Already performed a clean installation of avast ?
Any other security (related) software installed (or did you have) ?