Upload photos button is not working

My problem is simple:

I cant upload any photos onto lightroom.

Whenever I click the "plus" button in the upper left hand corner it simply doesnt react. 

I reinstalled the apllication and also restarted and updated my laptop but nothing is working.

The lightroom version is versio. 3.2.1 and my mac is updated to version catalina 10.15.4.

Hope someone can help me solve this problem.