Ubuntu 18.04 can’t wake after screen lock!

There seems to be an issue with N driver. Edit the grub file by editing it with sudo access.

  sudo vim /etc/default/grub 

change GRUB_CMDLINE_LINUX="" to GRUB_CMDLINE_LINUX="nouveau.modeset=0" and run

    sudo update-grub

Reboot after successfully updating grub file.