I have a number of servers running Ubuntu 18.04, all of which stopped updating anything on Dec 17. No errors seen in the unattended-upgrades or unattended-upgrades-dpkg log files.
If I do apt-get update I see some stuff download, but if I do apt-get upgrade nothing upgrades. This is despite running old kernels that have had recent vulnerabilties for which there are upgrades.
Anyone know the best way to troubleshoot why this is (or isn't!) happening?
Mirror in use is