[cups] printer detected by CUPS, browser interface not working ...

[Joe Weinberg]

 While using Debian Live:

 $ uname --all
 Linux debian 3.16.0-4-686-pae #1 SMP Debian 3.16.36-1+deb8u1 (2016-09-03) i686 GNU/Linux

 I connected a Canon imageCLASS D300 using its USB port
 
 $ lsmod | grep usblp
 usblp                  17090  0 
 usbcore            171098  5
 usblp,usb_storage,ehci_hcd,ehci_pci,usbhid
 
 $ sudo /usr/sbin/lpinfo -v | grep direct
 direct hp
 direct usb://Canon/imageCLASS%20D300?serial=2289HKMc
 direct hpfax
 
 but I can't manage it via the browser interface. When I:

 a) try: localhost:631
 b) click on add printer
  
 I get a authentication error:
 "A username and password are being requested",
 that I can't pass after trying many options

 How can use set up the printer in any
 other way for okular, firefox or konqueror 
 to be able to use it?
 
 lbrtchx