I have found that version 2.2.8 that comes with Ubuntu 18.10 works fine. I downloaded and installed it into Ubuntu 18.04 from https://launchpad.net/ubuntu/+source/cups/2.2.8-5ubuntu1.2 and it asked for login and all admin functions were working as expected.
I have found that version 2.2.8 that comes with Ubuntu 18.10 works fine. I downloaded and installed it into Ubuntu 18.04 from https:/ /launchpad. net/ubuntu/ +source/ cups/2. 2.8-5ubuntu1. 2 and it asked for login and all admin functions were working as expected.