blank login screen after reboot

[goron]

HI,

Im new to this forum. I recently installed kubuntu and tried to change my lock screen from system settings. When I reboot the system. I no longer see the login screen. Its just blank with the cursor.

However I had to CTRL+ALT+F2 for tty session and changed my display manager to gdm3

sudo dpkg-reconfigure sddm

and choose gdm3 ..

Here are the version specific information:

$plasmashell --version
plasmashell 5.12.9

$kf5-config --version
Qt: 5.9.5
KDE Frameworks: 5.44.0
kf5-config: 1.0

$ cat /etc/lsb-release                         
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=18.04
DISTRIB_CODENAME=bionic
DISTRIB_DESCRIPTION="Ubuntu 18.04.3 LTS"

How can i fix this issue.. Please let me know if you need any additional information.

Thanks.