This is probably related to the permanentMAC address matching, which was invalid and got dropped in newer version of Netplan, as MAC address matching is not supposed to be used on virtual interfaces (such as the Loopback interface).
Could you please try removing the "match. macaddress: 00:00:00:00:00:00" setting (and "set-name: lo"). That way it should match on the "lo" interface automatically and IP addresses should be assigned. In the future, you might be able to use "dummy-devices" in Netplan, instead of "lo". ** Changed in: netplan.io (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2055333 Title: netplan.io 0.106.1-7ubuntu0.22.04.2 fails to manage additional loopback addresses on Ubuntu 2204 Jammy To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/netplan.io/+bug/2055333/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs