Symptoms
The "Zone Editor" option does not appear in the "Advanced" tab in "Manage Website" in WP Squared for accounts created using a subdomain (sub.domain.tld vs domain.tld).
The following error will appear in the upper-right corner when accessing "Manage Website" for the subdomain.
You do not control a DNS zone named "domain.tld".
Description
This is caused by the account not having control of the main domain for the subdomain.
We've opened an internal case for our development team to investigate this further. For reference, the case number is WPX-9322. Follow this article to receive an email notification when a solution is published in the product.
Workaround
The account can be created for the main domain, and then a new site added for the desired subdomain.