The automatic alias for virtual server does point to the still unregistered DNS name instead of serving the actual content

I did this to the letter (found in the FAQ):

Another method, and the way we’d recommend, is to setup an alias so that your customer could access their site using http://username.mydomain.tld. You can do that by going into System Settings → Server Templates → Default Template → Virtual Server Creation, and adding your primary domain in “Automatically create alias domain”. This makes it so that any new Virtual Server created will have not only the domain you setup, but also an alias your customer can use before the DNS is pointing to your server.

But when I try to preview the site by opening the alias i get ‘ERR_NAME_NOT_RESOLVED’ error in chrome (unable to resolve domain).

I checked and the alias is redirecting instead of serving the website. I see this happen for sub-server aliases too ( redirects to sub.domain.tld).

Anyone could help me correct this behaviour ?

I am using the GPL version of Virtualmin on CentOS Linux 7.6.1810

Webmin version 1.900 Usermin version 1.751
Virtualmin version 6.06 Authentic theme version 19.33-beta3
Time on system Monday, May 20, 2019 12:24 PM Kernel and CPU Linux 3.10.0-957.12.1.el7.x86_64 on x86_64