Logging into a freshly installed VPS (KVM) and after installing Virtualmin I noticed the IP address that appears next to the host name is not the dedicated IP address of the server but 127.0.0.1.
System Information > System | System hostname vps.example.com (127.0.0.1)
Hmm, what are the contents of your /etc/hosts file now?
I suspect you may have corrected it, and that Virtualmin just isn’t reflecting that change yet. But verifying the contents of your /etc/hosts file should help.