Failed to start light display manager See systemctl lightdm.servicw

[saad]

I was trying to change settings in lightdm. After that I restarted my PC and I no longer had a gui login screen or something like that.
I searched and found some solutions. Some are saying to open terminal by Ctrl+alt+F1, some are saying to press Ctrl+alt+F2. After pressing it a black screen is coming but I can't give any command.
Now, how can I change login screen lightdm to gdm3 at this situation? Or any other solutions?
Thanks in advance.

@Aravisian Sir, please help me.

[Aravisian]

@saad

I was trying to change settings in lightdm.

What changes were you making and what steps did you follow?

[saad]

I was trying to get lightdm-webkit-greeter.conf to use the theme of this link-GitHub - paysonwallach/aqua-lightdm-webkit-theme: A macOS-inspired LightDM webkit greeter theme.
but it was not available in lightdm directory.

So, I searched for it and wanted to add lightdm-webkit-greeter.conf.

I followed this link-

How can I install lightdm-webkit2-greeter?

And at the end I changed "/usr/share/lightdm/lightdm.conf.d/60-web-greeter.conf" files text with [Seat:*]
greeter-session=web-greeter and trued to reboot my PC.

[Aravisian]

On reboot, when you get stuck during boot, press ctrl+alt+F2 to enter the tty console mode.
Check the status of the service:

systemctl status lightdm

If you see status as green try launching LightDM in debug mode to show you any errors:

lightdm --test-mode --debug

If status is red, try:

sudo apt install --reinstall lightdm

[saad]

I tried this before, what ever I type, nothing is being written

Just a white "-" is blinking.

[Aravisian]

Can you boot into recovery mode?
Tap esc or tab if needed to show the Boot Grub Menu
Choose Advanced Options for Zorin Zorin with 5.13 - recovery
Arrow key down to Drop to Prompt

You may need to run:

sudo dpkg-reconfigure lightdm

sudo service lightdm restart

[saad]

Is it that grub?
If yes, then it's not working

[Aravisian]

After grub> _
Type

exit

then relay what errors it shows

[saad]

No error.
Just got to the previous page.

[Aravisian]

This is a new one... That is a line of failure points that I have never gotten to this point before.

[saad]

Then, should I reinstall zorin os?

[Aravisian]

That is one possible solution. I mean... It would solve the issue. I think we both would prefer that you got Terminal Access in order to affect changes to the system.
Using the TTY above, the Recovery Menu above, are both methods of doing so.
If unable to access the terminal, then it really reduces our chances of avoiding a reinstall.

[saad]

Ok, Thanks.