UR12 set up

I’ve got a steinberg ur12 audio interface it work fine for everything ie youtube ex. but when I open cubase LE AI elements 9.5 it will not?

when I first open cubase its gives me the option to use the ur12 or built in monitors
I click ur12 then it tell me

the audio driver could not be loaded, please make sure your audio hardware is connected correctly to your computer

then automatically just plays though the built in monitors

can any one help please ???