Whenever I run the software app, I’m unable to search for anything as nothing is ever actually found. All I see is the blank screen with a spinner, and it never stops. I can search for software that is displayed right there in the list when I first open the app and still, nothing is found. Likewise, if I click directly on a software app, again, all I see is a blank page with the spinner… I’m running UB 20.04, I have kept up with all the updates, I have no other system problems, can access the internet, etc. Does anyone have an idea what could cause the software app to act this way? Thanks for any help!
That did it! Thank you so much, fossfreedom! 
That has been bothering me for a few months now. I had no idea what was going on. In my case, the "gnome-software’ folder didn’t already exist so I just did the “killall” command and the “mkdir” command and then re-started the software app and it immediately began updating the software cache or whatever like it should.