Did you previously activate your licence key on a different domain?

Sometimes, a site is activated when it is a development domain, and when the domain is changed, you would need to deactivate the licence, then activate it again, so the live domain name is activated and registered on our server. So, check if Your Account shows a domain already activated?

You might need to deactivate that domain, wait over an hour (this is important to let our cache clear) and then reactivate, and then wait again.