Hello,
I will ask our support team to send me the support request. I will need a support package (application’s Help menu → Avast Technical Support → Generate support package) to see, what is the license state on the device.

We had an error in the product that the license information was overwritten with a legacy data recently. The activation code was sent to you a part of purchase confirmation email. If there’s no activation code in the application preferences, could you please try to find the confirmation email and enter the activation code to the preferences?

Best Regards,
Martin