Packer Ubuntu server 20.04.6 live server keeps prompting for install conformation

I am trying to setup an unattended installation (building a VMWare template) with Packer and Ubuntu 20.04.6 live server, using an autoinstall user-data config file.
The problem is that the Ubuntu installation prompt for confirmation, despite of my user-data file.

The message is:
“Add autoinstall to your kernel command line to avoid this.
Continue with autoinstall? (yes/no)”

Help please!

This indicates you need to add “autoinstall” to the boot_command of the source in your packer file.

I have the below configuration, but still failing.

“boot_command”: [
"/casper/vmlinuz ",
"root=/dev/sr0 ",
"initrd=/casper/initrd ",
"autoinstall ",