This problem is related to the path:
Webmin=>Networking=>Network Configuration=>Hostname and DNS client=>DNS Servers.
I recently changed my DNS server to a remote machine (to run some tests).
I have completed tests so I am now including the IP address of my local machine so I can access Virtual Server domain names from the browswer.
(minor) problem: each time I power up or activate from saved state its resetting itself to the previous (unwanted) value. Virtualmin is clearly saving and retrieving state