@slawa-jad I don’t think grub_is_lockdown is the issue, just the message presented.
If you’re able to load up the original machine you captured the image from, look at your /etc/fstab file.
I suspect you’ll see something to the effect of:
UUID=a2476193-12cf-4601-a38d-6c798fc42708 /boot                   ext4    defaults        1 2
UUID=AACD-BEFE          /boot/efi               vfat    umask=0077,shortname=winnt 0 2
If your file.
This is where things are breaking down.
Change the UUID= portion to the actual drive name.
The boot efi part, I’m not 100% certain what to change it to, but I would suspect probably
/dev/sda1 /boot                   ext4    defaults        1 2
/dev/sda2          /boot/efi               vfat    umask=0077,shortname=winnt 0 2
This is just my guess. I would not make these changes on the “originally captured” machine but rather make it on one of the machines that you deployed to and fix it there. Once it’s fixed, I’d then suggest re-capturing the image from that “now working” machine and deploy as freely as needed.