I can't record on audacity

I was using audacity for a while now. but lately I wanted to record something but I can’t. when I press the record Botton it start to record but there is no audio being recorded. it’s just empty, I’ve checked the mic and it is working perfectly and I’ve tried with my headphones. and it seems like there is problem. I even deleted the app and download it again and i still have same problem.
please I need help. thank you in advanced.

Which version of macOS?
Which version of Audacity? (look in “Audacity menu > About Audacity”)
What are you trying to record?
What sort of mic?