You do not add the panel domain inside the panel's dns manager nor domain manager. You will need to manually update the panel's domain in the database and in several config files (which I do not know offhand, like dovecot, postfix, etc.) And I can't be sure if the panel will even work correctly on a domain instead of a subdomain.
You are attempting to use/access the panel in a manner that it was not designed for.
You are attempting to use/access the panel in a manner that it was not designed for.
