How to setup new domain on Virtualmin

[calport]

This should answer all your questions

Primary nameserver is not valid

In addition to what @Joe and @ramin said, you should set up 5 domains in the following manner for the best installation experience with Virtualmin: Create and set domain.tld and www.domain.tld to IP address of the server on which Virtualmin will be installed. These domains will become the first hosted domain that you will use under Virtualmin. Create and set vps.domain.tld to IP address of the server on which Virtualmin will be installed. This will be the hostname that you will use for you…

You really should RTFM and the messages on these forums a bit more, @samito.