It means the purchase code is registered to a different domain.
This could mean that:
The purchase code is registered to a website with a different domain.
The website has migrated to a new domain, but the purchase code was not unregistered from the original domain.
The domain name is the same, but the domain URL has changed. For example, the “www” prefix has either been added or removed from the URL and no longer matches the domain URL the purchase code is registered to.
To resolve this, you can log into your support account, navigate to the “Licenses” tab and manage the sub-domain and top-level domain registration there > https://my.avada.com/licenses/ and click the unlink icon next to the domain type for the specific purchase code – https://d.pr/i/4UYWT6
Once you have done this, you can navigate to the Avada Dashboard from the backend of your site and complete the registration.