Failed to create virtual server : The domain is already hosted by your Apache webserver - sub-domain is used already

I created a new server a while back with Ubuntu 18.04, Apache and installed Webmin using as the URL for the installation.

I now want to host on that server but cannot Create a Virtual server for because it is already ‘hosted’ by Apache. At least the sub-domain is and that seems to prevent the root domain from being created.

Is there a simple way around?