I believe I have encountered this issue in a fresh install of Trusty. I was able to add a network printer only with "gksudo system-config-printer". Otherwise, my credentials were refused and I could get part way through printer installation, but could never complete it. I could cancel so the credentials dialog went away, but it came up again when I clicked on "apply" at the end of the install.
I believe I have encountered this issue in a fresh install of Trusty. I was able to add a network printer only with "gksudo system- config- printer" . Otherwise, my credentials were refused and I could get part way through printer installation, but could never complete it. I could cancel so the credentials dialog went away, but it came up again when I clicked on "apply" at the end of the install.