@toreskev is right. Your install is bogus in at least a couple of ways we can obviously see, and we can’t guess at what other ways it is bogus. You should start with a fresh/clean supported OS installation, and then run our install script on it following the instructions on our download page.
I’m happy folks are offering pre-installed Virtualmin, but I wish they’d get it right. I don’t even know how they’d end up with it broken in this particular way.