Error in Packer vSphere ISO for Ubuntu 20.04.3

Packer
1

@bladnor : I saw your reply here and I was very happy with your clear explanation. Can you please help me too. Here are the details.
Packer Version: 1.7.4
vSphere Client version: 6.7.0.48000
Ubuntu version: 20.04.3
Builder Type: vsphere-iso

Here is my builder.

"builders": [       
     {
      "type": "vsphere-iso",
      "vcenter_server": "my-vCenter-Server",      
      "username": "myUser@vsphere.local",      
      "password": "vSphereUserPwd",
      "insecure_connection": "true",    
      "datacenter": "my-DataCenter",
      "cluster": "myCluster",
      "datastore": "datastore1",  
      "guest_os_type": "ubuntu64Guest",
      "host": "my-host-name",
      "CPUs": 2,
      "RAM": 2048,
      "RAM_reserve_all": true,
      "firmware": "bios",
      "disk_controller_type": "pvscsi",
      "storage": [{
        "disk_size": 20480,
        "disk_thin_provisioned":true
      }],
      "network_adapters": [{
        "network": "myVLAN", 
        "network_card": "vmxnet3"
      }],
      "name": "Ubuntu-20.04",
      "vm_name": "ubuntu-server",
      "folder": "MY-FOLDER",
      "notes": "Built via Packer",            
      "convert_to_template": true,
      "ssh_username": "myUser",      
      "ssh_password": "myPwd",
      "ssh_timeout": "20m",
      "ssh_handshake_attempts": "100000",
      "iso_paths": ["[datastore1] ISO/ubuntu-20.04.3-live-server-amd64.iso"], 
      "iso_checksum": "sha256:f8e3086f3cea0fb3fefb29937ab5ed9d19e767079633960ccb50e76153effc98",
      "http_directory": "{{template_dir}}/http",
      "cd_files": ["{{template_dir}}/http/user-data", "{{template_dir}}/http/meta-data"],
      "cd_label": "cidata",
      "create_snapshot": "false",
      "boot_wait": "2s",
      "boot_command": [
        "<esc><esc><esc>",
        "<enter><wait>",
        "/casper/vmlinuz ",
        "root=/dev/sr0 ",
        "initrd=/casper/initrd ",
        "autoinstall ",
        "ds=nocloud-net;s=http://{{ .HTTPIP }}:{{ .HTTPPort }}/",
        "<enter>" 
      ],
      "shutdown_command": "echo 'ubuntu'|sudo -S shutdown -P now"     
     }        
    ]

user-data content is as below

#cloud-config
autoinstall:
  version: 1
  apt:
    geoip: true
    preserve_sources_list: false
    primary:
    - arches: [amd64, i386]
      uri: http://gb.archive.ubuntu.com/ubuntu
    - arches: [default]
      uri: http://ports.ubuntu.com/ubuntu-ports
  identity:
    hostname: ubuntu-server
    username: ubuntu
    password: encrypted-password
  ssh:
    allow-pw: true
    install-server: true
  locale: en_US
  keyboard: 
    layout: gb
  storage:
    layout:
      name: direct
    config:
      - type: disk
        id: disk0
        match:
          size: largest
      - type: partition
        id: boot-partition
        device: disk0
        size: 500M
      - type: partition
        id: root-partition
        device: disk0
        size: -1
  late-commands:
    - "echo 'Defaults:ubuntu !requiretty' > /target/etc/sudoers.d/ubuntu"
    - "echo 'ubuntu ALL=(ALL) NOPASSWD: ALL' >> /target/etc/sudoers.d/ubuntu"
    - "chmod 440 /target/etc/sudoers.d/ubuntu"

I have tried so many combinations for boot command, user-data and so on. But I always encounter the following error.

command [‘systemd-cat’, ‘–level-prefix=false’, ‘–identifier=subiquity_log.2014’, ‘.snap/subiquity/2651/usr/bin/python3’, ‘-m’, ‘curtin’, ‘–showtrace’, ‘-c’, ‘/var/log/installer/subiquity-curtin-install.conf’, ‘install’] returned non-zero exit status 3

Can you please help? I am running packer build from another ubuntu 20.04.3 server