The activation code only has a limited number of uses, but the license file can be used without limitation.
If you haven’t saved or can’t find your license then try the - Resend avast License https://www.avast.com/resend-license-paid.php, you will need to enter the email that you used when purchasing the license, e.g. the one that the original email with the link was sent.
You could also log on to your my.avast.com account and assign your license to your installation.
