Hi Michal,
Thank you for your quick response. SecureBoot was turned on, but even after I turned it off, it doesn't work. At one point after computer restart, I got Ubuntu crashed due to the problem with DisplayLink. Please check attached screenshots.
Screenshot from 2017-12-08 10-14-45.jpg
Screenshot from 2017-12-08 10-16-39.jpg
I also can login only on "Ubuntu Xorg" but not on "Ubuntu". I've tried uninstalling and installing again.
Thanks,
Zoran