Hi @adib, we’ve found this to be a result of firewalls, either on a software or network level. Our activation system connects to a 3rd-party server and checks the serial against the database. That connection is either being blocked or the activation file/key is being deleted from your system. That would be caused by an app like CleanMyMac or MacKeeper, for example. In some scenarios, there’s not anything that can be done to solve this if removing those apps and adjusting firewall are not an option.