Not able to provision Baremetal VM (VirtualBox) using the latest MAAS 2.6.1

Team,

I’m trying to setup MAAS in virtual box, and provision a Baremetal VM. I was able to provision the server using the old 2.3 version in 16.04. I recently migrated to 18.04 MAAS 2.6.1, I’m unable to provision the server now its failing in the PXE.

Below are the error message:
Could not select: Exec format error (http://ipxe.org/2e008001)
Could not boot: Exec format error (http://ipxe.org/2e008001)

I tried to change the base image to 16.04, looks like its not allowed.

Any help on how to move forward is much appreciated.

Thanks,
Senthil Kumar G.