It seems that somehow my user got added to the nopasswordlogin group.I solved this by going into the terminal and typing in the command line: sudo gedit /etc/group and deleting my user name from the nopasswdlogin group in the text file and then saving the file again. Now I can lock the screen and the system requests a password on the ubuntu login screen.
It seems that somehow my user got added to the nopasswordlogin group.I solved this by going into the terminal and typing in the command line: sudo gedit /etc/group and deleting my user name from the nopasswdlogin group in the text file and then saving the file again. Now I can lock the screen and the system requests a password on the ubuntu login screen.