reboot but got black screen

[ZhenshengWu]

hey man！
firstly，the system of my service is ubuntu18.04 LTS and the version of Nvidia-drive is 460.23.The screen output through CPU.So when i run "sudo nvidia-xconfig -a --cool-bits=28" it make a new "xorg.conf" but after rebooting the service ,Black screen before user login interface. I remotely logged in via SSH and deleted the xorg.conf file,and rebooted .it can boot normally,but nothing changed in my computer.
How can solve this problem.Thank you!

[ZhenshengWu]

I forgetd to tell you that the Graphics card is RTX3090*8 . And It work in you way in a computer with an RTX2080Ti,and the output of sreen via RTX2080Ti.