Login page doesn't appear

Whenever I boot my laptop, my Ubuntu 20.04 doesn’t show login page and just shows a cursor in a black screen.

I find out by pressing Ctrl+Alt+F2 and then pressing Ctrl+Alt+F1, the login page appears.

How can I fix it?

>Solution :

from the archwiki https://wiki.archlinux.org/title/GDM

GDM does not start until switching TTY and back

If, after booting, the screen stays black and GDM does not start until
changing to another TTY and then back to TTY1, it may be because GDM
is being attempted to run before GPU driver is loaded.

One possible solution is adding your GPU driver module to be built
into initial ramdisk with mkinitcpio, by adding the module name into
MODULES entry in /etc/mkinitcpio.conf. Make sure that initcpio files
get generated afterwards.

An alternative walkaround is to add delay to GDM service file.

# systemctl edit gdm

[Service]  
ExecStartPre=/bin/sleep 1

try to run the below command to edit the gdm file

sudo systemctl edit gdm

put above two lines below the last lines of the opened file. If delay of 1 sec is not working try to increase the delay.

save and restart the gdm with below command

sudo systemctl restart gdm