created a site with a .rocks domain. Bind nameserver shows it as .xn--rocks-5d33a

created a site in virtualmin with a .rocks domain. Bind nameserver records shows it with a “.xn–rocks-5d33a” extension .
What is that??

Your domain name is in english or you have language specific characters like in Italian, French, German… Russian… and so on?

Yes, regular english alphabet letters, no characters.
I’m not sure if virtualmin does a DNS check first.
The servers are virtual cloud servers.
It does that also for a fake domain name .rocks.

Virtual server details
Domain name:
Real DNS domain name:

This was solved.
It was the “Administration password” that had non-ascii characters. When I used a regular password, it worked.
But then shouldn’t the administration password accept the non-ascii characters?
Somehow the password got included in the non-ascii characters domain name check.