DMC, could not enable bluetooth on Windows 10 XPS

Apparently Dell Mobile Connect was running for a long time, but I hadn't tried to use it until the other day when I was informed it couldn't turn on bluetooth.  I poked around and discovered it showed my phone as having been connected at one point, though I don't recall doing that.

In any case I've been all around the block, doing this reinstall of new drivers and the whole nine yards, including several uninstalls, reinstalls and restarts. Among others, tried this sequence : https://www.windowslatest.com/2018/01/15/install-dell-mobile-connect-app-wndows-10/

In every case,  I get to the point where I have put in the code that's on the phone side and the app responds with the very unhelpful "..could not enable bluetooth..." when I know it is already on.

And, when I go look at bluetooth settings, I no longer see a phone, but five other devices are connected.

How can this be fixed?