I experienced the same problem. Beginning with 15.07, Ubuntu has changed the default naming of network devices. ensXX is the new default. There are methods to force the old names with changes to Grub (
http://askubuntu.com/questions/767786/changing-network-interfaces-name-ubuntu-16-04)
However, since this is an appliance that is being provided to us and you built it on Ubuntu 16.04, it would make sense that you either modify your script to detect the new name or enable the Grub nickname override.