Can´t add alias domain

Access Denied adding released subdomain timekeeper.lifebeat.dk

I cannot add timekeeper.lifebeat.dk as a domain alias to my project
lifebeat-timekeeper. The UI returns only “Access Denied”.

Sequence so far:

  • The domain was held by a project in a rocket.new account I have no
    access to. They have now released it. The hostname currently returns
    404 from Netlify, so no project appears to hold it.
  • Adding it as an alias first gave “Another project is already using this
    domain”. After the release it gives “Access Denied” instead.
  • I removed the previous owner’s netlify-challenge.lifebeat.dk TXT
    record. Still “Access Denied”.
  • The automated domain-release form rejects the name because it is a
    subdomain: it appears to require NS or SOA at the exact name, which a
    subdomain does not have.

I control the zone lifebeat.dk, authoritative nameservers ns1.curanet.dk
and ns2.curanet.dk, and I have published:

verified-for-netlify.timekeeper.lifebeat.dk TXT lifebeat-timekeeper.netlify.app

My project is lifebeat-timekeeper, primary domain timekeeper.life, which
is working correctly. I only need timekeeper.lifebeat.dk attached as an
alias so the old address redirects to it.

The old address is currently serving 404 to real users, so this is
affecting people rather than being cosmetic.