I have the same problem when upgrading from 10.04 to 10.10.
I'm behind proxy with basic auth (squid), proxy settings sets in env and apt.cont. Installing and updating packages works well.
> sudo do-release-upgrade
do nothing, so I replaced /var/lib/update-manager/meta-release from http://changelogs.ubuntu.com/meta-release manualy, then all works fine.
I have the same problem when upgrading from 10.04 to 10.10.
I'm behind proxy with basic auth (squid), proxy settings sets in env and apt.cont. Installing and updating packages works well.
> sudo do-release-upgrade update- manager/ meta-release from http:// changelogs. ubuntu. com/meta- release manualy, then all works fine.
do nothing, so I replaced /var/lib/