VirtualBox VM PXE boot install fails with err:3c092003

I am using VirtualBox and have two VMs VM A: - NAT networking adapter - Host-only networking adapter - Internal Network adapter (network is called "test") and VM B: - Internal Network adapter (network is called "test") I am following that article: https://wiki.debian.org/PXEBootInstall to learn how to boot a client VM (VM B) using a network boot server (VM A) I "manually" assigned the internal adapter network card of VM A with IP

eth2 192.168.0.1 netmask 255.255.255.0 up

I then started the dhcp and tftp servers on VM A using the following configurations: /etc/dhcp/dhcpd.conf:

default-lease-time 600;
max-lease-time 7200;

allow booting;
option architecture-type code 93 = unsigned integer 16;

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.2 192.168.0.253;
  option broadcast-address 192.168.0.255;
  option routers 192.168.0.1;             
  option domain-name-servers 192.168.0.1; 
  filename "pxelinux.0";
}

group {
  next-server 192.168.0.1; 
  host tftpclient {
    if option architecture-type = 00:07 {
      filename "debian-installer/amd64/bootnetx64.efi";
    } else {
      filename "pxelinux.0";
    }
  }
}

/etc/default/tftpd-hpa:

TFTP_USERNAME="tftp"
TFTP_DIRECTORY="/srv/tftp"
TFTP_ADDRESS="0.0.0.0:69"
TFTP_OPTIONS="--secure"

When I power-on VM B, I see

Waiting for link-up on net0... ok
DHCP (net0 08:00:27:3a:f4:34)...... ok
net0: 192.168.0.2/255.255.255.0 gw 192.168.0.1
Filename: pxelinux.0
Could not start download: Operation not supported (http://ipxe.org/3c092003) 
No more network devices

I tried googling for the err:3c092003 and saw articles suggesting: - that I might be running VirtualBox which doesn't support HTTP (https://forum.ipxe.org/showthread.php?tid=7068) - however on iPXE welcome message I see Features: DNS TFTP HTTP PXE PXEXT Menu so that shouldn't be the case (HTTP is in the list) - that I am trying to open a URI using a protocol that is not supported by my current build of iPXE (https://ipxe.org/err/3c0920) , however, looking at the suggestions steps there I can't seem to find a way to fix it Any help would be greatly appreciated! Update: I am on macOS Big Sur VirtualBox version 6.1.28 r147628 (Qt5.6.3) VM A and B are with Debian 3.16.7-ckt20-1+deb8u3