Recording issues with Steinberg CI 1

Hi all,
I’ve had ‘CI 1’ for few years now, and mainly used it for recording guitar - and there was never an issue there. Recently decided to record some microphone sounds, but I can’t.
I’m using ‘Reaper’ as my DAW.
I use headphones for playback on ‘CI 1’.
I’ve tried all I could think of : switching on and off Mic itself, pressing [phantom] button, pressing [mono] button, playing with levels, choosing mono or stereo on DAW, trying different driver, reducing buffer size. Absolutely nothing is happening. When I arm my track, enable monitoring and pressing ‘Record’ on 'Reaper, all I see is a thin line and not a single wave.
Any pros here could tell me what to do?