Some problematic computers rebooting can hang or freeze, so the solution is to add reboot=bios or reboot=acpi to the /etc/default/grub file and update grub after editing.

In openSUSE grub updage goes using command

sudo grub2-mkconfig -o /boot/grub2/grub.cfg

In Debian based systems it goes

sudo update-grub

Found from https://www.suse.com/support/kb/doc/?id=000017792