Support for build 1903 was only added to the drivers recently. This is where the "Windows as a Service" model breaks down. Newer drivers don't support your hardware, older drivers that support your hardware won't work with build 1903. Hopefully you can roll back to the build you were on before. That's my suspicion anyway.
Or maybe Windows just stomped your drivers when it upgraded. When I upgraded to 1903, it replaced my 19.7.2 driver with a 19.4.X driver, which didn't match the Radeon Settings app which refused to work. If it upgraded you to a new driver that doesn't support your hardware...
Try a safe mode DDU uninstall and try re-installing 16.2.1 Beta. If that doesn't do it try rolling back to your previous Windows build.
