Midi not being recorded????? Cubase 8.5 pro

Hi everyone, hope someone can help. I’ve suddenly develped a strange problem in Cubase 8.5 pro.
When I play my USB midi contoller keyboard into cubase, I can hear the Steinberg Grand piano play no problem. But when I try and record a track, no midi is being reorded? the track is blank??? It’s the same if I load another instument track…I can play the instument , but when I try to record it the track is completey blank…no midi info. I’ve tried everything, reloading Cubase, re loading keyboard drivers, but still no midi being recorded? I’m really frustrated and baffled. In device manager I can see the keyboard controller, just don’t know whats gone wrong. Can anyone please help, cheers Darren

And of course the first thing you sid was checkong the MIDI filters, wasmt it?