SOLVED: Lightroom CC starts importing, then progress bar disappear and finally import is grayed out

I just bought a brand new Macbook Pro 2019 two weeks ago. I installed Lightroom. Everything was working fine. Then, yesterday, Lightroom just began to stop importing. When I try to import a photo, regarless from where are the files, the import starts as normal, I see the progress bar appearing at the top left corner, then it disappears after 3 seconds. I then try to reimport the files, but now the Import option is grayed out from the menu. 

I tried uninstalling and reinstalling it. Didn't work.

I tried to reset the preferences. Didn't work either.

I also tried to downgrade to an older version of Lightroom. Didn't work too.

Can you please help me?

I use Lightroom Classic 9.2.1 with MacOS Catalina 10.15.4