I have a server running Ubuntu 14.04.4 LTS (GNU/Linux 3.13.0-147-generic x86_64).
After initial setup, I installed and enabled Unattended Upgrades.
For about 9 months Unattended Upgrades worked fine.
However, it seems that about 8 weeks ago it stopped working. On login I now see the notification "79 packages can be updated. 9 updates are security updates."
At this stage I am only concerned about the security updates.
I have tried re-installing Unattended Upgrades. I have also checked the settings which seemed to be most relevant after investigating this matter online. However, nothing seems to work.
I have also tried to upgrade manually using "sudo unattended-upgrade -d". Again, it does not work. It gives the output (here abbreviated):
Initial blacklisted packages: Starting unattended upgrades script Allowed origins are: ['o=Ubuntu,a=trusty-security', 'o=UbuntuESM,a=trusty'] ... pkgs that look like they should be upgraded: Fetched 0 B in 0s (0 B/s) fetch.run() result: 0 blacklist:  Packages that will be upgraded: InstCount=0 DelCount=0 BrokenCount=0
Can someone help me with this, please?