No audio output on Cubase 8.5 with Fast Track C400

This is Cubase Artist 8.5 and 8.5.20 on Windows 10.

I’ve had this problem for a while now. When I want to record audio through my Fast Track C400, no sound is put out, even if the sound input is working fine. I can see the input/output meters moving when I play on the keys, or talk in the mic But there’s no sound at all.

BUT, if I switch to the generic ASIO driver, sound plays as it should, but not when I choose the Fast Track driver.

It used to work intermittently, but not anymore.

What the matter? Is it the Fast Track box that has broken? Is it Windows 10? ( I was running Win 10 when I bought Cubase.)

Any advice would be great!