FlatHub requires verification on wrong domain

FlatHub requires to verify my app: Install CoBang on Linux | Flathub

It tells me to:

Create a page at https://hoabinh.vn/.well-known/org.flathub.VerifiedApps.txt containing the following token

But hoabinh.vn is just a top-level domain, managed by Viet Nam Internet Network Information Center. My domain is quan.hoabinh.vn.

See Fix verification for country-specific domains · Issue #4943 · flathub/flathub · GitHub

We currently don’t support those kind of urls for verification