SmartDeviceException - Class not registered when deploying UAP to device

When pressing start with "Device" selected for the first time, I get...

Severity Code Description Project File Line Suppression State Error DEP0001: Unexpected Error: SmartDeviceException - Class not registered [0x80131500] UWP

What does this mean?

Which class is not registered?

The device is a Nokia Lumia 830. I recently upgraded it to Windows 10. It's running 10.0.14393.1770.

The app is targeting 16299, with minimum 10586. I've tried upgrading the phone, but I think it installed 14393 twice in a row.

I've tried reinstalling Visual Studio 2017.

Developer mode is switched on on the phone and the dev machine.