Proxmox: enp0s31f6: Detected Hardware Unit Hang

Since a few weeks, my Proxmox lab has started having issues with on-board network. The adapter enters in “hang” state, the logs are full of recurring errors like below:

Initially I was suspecting a hardware issue but after replacing

Chef resources failing with wrong constant name

When trying to add a custom resource, no matter what, I always got a  wrong constant name  error, for example:

It turned out to be an issue with my cookbook name: it’s not allowed to have a cookbook name starting with a number