Clone Tool Isn't working

[stathisp6930936]

Hi guys, 

The Clone Tool stopped working properly in Photoshop (I have a i7 pc, Nvidia graphics card, windows 10). The steps I followed so far are listed below:

1) Re-installed and installed Photoshop 2020.

2) I reset the clone tool. 

Here are my preference settings. Any help will be much appreciated.