Some machines get this error while commissioning:
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package lldpd
When going into rescue mode and manually doing apt update:
sudo apt update
Err:1 http://archive.ubuntu.com/ubuntu focal InRelease
Connection failed [IP: 10.8.8.183 8000]
Hit:2 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://archive.ubuntu.com/ubuntu focal-security InRelease
Hit:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease
It seems to be a random problem with the APT proxy in MAAS.
If I switch to an external proxy (standard HTTP proxy), it just works.
How can this be debugged?