All my .com domain sites work perfectly, including subservers.
However, I’m unable to get the .com.au and .org sites to work.
They appear in Virtualmin Website Preview OK,
But always show up as “This webpage is not available” DNS lookup failed, when searching for the domains.
So I know it’s a DNS issue.
From Virtualmin’s point of view, all the domains you mentioned above should be the same. It doesn’t treat a .com domain differently than a .org.au domain.
It’s possible you’re seeing a nameserver issue – perhaps the nameserver setup for the working domain is different than that of the non-working one?
You could try something like intodns.com to get a DNS report, and see if it detects any problems.
Also, if you let us know your domain name that isn’t working, we could run some tests of our own to see if the issue stands out. You can always remove the domains from the Forums later, once things are working.