This error occurs because of the graphics card as the Ubuntu installer doesn't have graphics driver for processing the GPU output.
Similar error may come after a successful installation of any Linux distro on a PC with dedicated graphics card.
A solution which works in both the cases is to switching the graphics driver.
When you get the boot options for Ubuntu from the LiveUSB select "Try Ubuntu without installer". Do not press Enter just select it.
There would be some settings in form of labels and values
Go to the Linux lable and at the end of the value add
Press F10 to save and exit.
Press Enter and follow the rest of the tutorial
The same solution works if the problem occurs after successful installation
The permanent solution:
After successfully installing Ubuntu install Nvidia driver 440/430/390 according to your preference by running following command in terminal. For 440, run,
sudo apt install nvidia-driver-440.
Reference: fix any linux booting problem - YouTube