I want to upgrade my ubuntu 14.04 distribution to the 16.04.
I'm working in a domain buy I have sudo permissions, the repositories point to our private repositories
I try to upgrade with the command do-release upgrade and the application and I got this error.
$ sudo do-release-upgrade Checking for a new Ubuntu release Get:1 Upgrade tool signature [198 B] Get:2 Upgrade tool [1262 kB] Fetched 1262 kB in 0s (0 B/s) authenticate 'xenial.tar.gz' against 'xenial.tar.gz.gpg' gpg exited 1 Debug information: gpg: Signature made dc 26 oct 2016 16:32:27 CEST using DSA key ID 437D05B5 gpg: /tmp/ubuntu-release-upgrader-gzuou970/trustdb.gpg: trustdb created gpg: BAD signature from "Ubuntu Archive Automatic Signing Key <firstname.lastname@example.org>" Authentication failed Authenticating the upgrade failed. There may be a problem with the network or with the server.
And when I try to upgrade through Software updater I get this error.
How could I do this?