I'm trying to build a new print server on Ubuntu 12.04 + CUPS. (Coming over from other distros....want to standardize on Ubuntu, if I can make it work!)

I can use the basic Ubuntu System Settings to add a printer, but not the CUPS http://{hostname}:631 page for remote administration! The page comes up and most functions appear fine.

But try anything like the "Add Printer" button and a prompt asks "A username and password are being requested by http://localhost:631. The site says: "CUPS"--but then it doesn't appear to accepts ANY credentials (my sysop, root, nor Windows AD PrinterAdmins group members!!! "The connection was reset" is all Firefox shows...

Any ideas are appreciated!