I was able to fix this issue. I had to uninstall illustrator from creative cloud desktop app, then run the Adobe creative cloud cleaner tool for all apps. Restart the computer, and re-download illustrator 23.1, not illustrator 2020. Then open the file explorer, and turn the preview pane off then back on. Now I can preview all my illustrator files in the preview pane in Windows 10. Hope that helps.
Hello,
I finally uninstalled 2020 and 2019 and re-installed 2020 and it worked.
I think the problem might be due to the fact I didn't uninstall 2019 before installing 2020.
Thanks for the help.