Solaris 11.4 on ESXi 6.5 suddenly boot-looping

Tl;dr Solaris 11.4 won't boot on 2 machines because of what I believe is network issues. Need to know where I can find more info to troubleshoot.

I have two Solaris 11.4 systems running on VMware ESXi 6.5u2, which have suddenly (and seemingly for no reason) started boot-looping.
Both of them cite the same reasons for their failure to boot: inability to bring up network services and an inconsistency in the boot archive.
Letting them regenerate it on their own results in the same error and reboot on the next boot. Using a live CD to mount their ZFS root and generate a new boot archive, again, changes nothing. Below you'll see the messages they spit out at boot.

I'm not given any opportunity to investigate from the console unless I boot to a live environment. The same thing happens when I try to boot these systems in single-user mode.

Would anyone have any idea where I'd need to look to get more details on these issues and troubleshoot further? Has anyone encountered this issue before? Is there a simple solution that I've just missed?

Thanks for your time, and if you need any more info from me to help resolve this don't hesitate to ask.

Hi,

You say in your post;

But you seem to have missed out the boot messages.

Regards

Gull04

There's an image at the bottom of the post... if needed, I can repost it as text.