Hi Carsten, Looking at the attached VarLogDistupgradeMainlog.txt, it looks like the mirror you are using does not have information for the impish release:
2022-05-15 12:30:21,956 DEBUG examining: 'deb https://mirrors.tuxedocomputers.com/ubuntu/mirror/archive.ubuntu.com/ubuntu focal main restricted universe multiverse' 2022-05-15 12:30:21,956 DEBUG found apt-cacher/apt-torrent style uri https://mirrors.tuxedocomputers.com/ubuntu/mirror/archive.ubuntu.com/ubuntu 2022-05-15 12:30:21,956 DEBUG verifySourcesListEntry: deb https://mirrors.tuxedocomputers.com/ubuntu/mirror/archive.ubuntu.com/ubuntu impish main restricted universe multiverse 2022-05-15 12:30:21,957 DEBUG url_downloadable: https://mirrors.tuxedocomputers.com/ubuntu/mirror/archive.ubuntu.com/ubuntu/dists/impish/Release 2022-05-15 12:30:21,957 DEBUG s='https' n='mirrors.tuxedocomputers.com' p='/ubuntu/mirror/archive.ubuntu.com/ubuntu/dists/impish/Release' q='' f='' 2022-05-15 12:30:22,043 DEBUG error from httplib: 'HTTP Error 404: Not Found' Please select another mirror and try the upgrade again. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1973565 Title: Upgrade to 21.10 not working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1973565/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
