hp-setup fails to detect network printer (Officejet Pro 6230)

The GUI version of hp-setup fails to detect (and times out) to find my network printer (HP Officejet Pro 6230). Running hp-setup from the command line shows a unicode error:

 hp-setup -i

HP Linux Imaging and Printing System (ver. 3.15.2)
Printer/Fax Setup Utility ver. 9.0

Copyright (c) 2001-15 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

(Note: Defaults for each question are maked with a '*'. Press <enter> to accept the default.)

--------------------------------
| SELECT CONNECTION (I/O) TYPE |
--------------------------------

  Num Connection Description
            Type
  -------- ---------- ----------------------------------------------------------
  0* usb Universal Serial Bus (USB)
  1 net Network/Ethernet/Wireless (direct connection or JetDirect)
  2 par Parallel Port (LPT:)

Enter number 0...2 for connection type (q=quit, enter=usb*) ? 1

Using connection type: net

|Traceback (most recent call last):
  File "/usr/bin/hp-setup", line 351, in <module>
    device_uri = mod.getDeviceUri(devices = device.probeDevices(bus))
  File "/usr/share/hplip/base/device.py", line 486, in probeDevices
    detected_devices = slp.detectNetworkDevices(ttl, timeout)
  File "/usr/share/hplip/base/slp.py", line 115, in detectNetworkDevices
    x= to_string_utf8(x)
  File "/usr/share/hplip/base/sixext.py", line 113, in to_string_utf8
    return s.decode("utf-8")
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x95 in position 363: invalid start byte

==================================

Output from hp-doctor:

hp-doctor

HP Linux Imaging and Printing System (ver. 3.15.2)
Self Diagnse Utility and Healing Utility ver. 1.0

Copyright (c) 2001-15 Hewlett-Packard Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

-Xlib: extension "RANDR" missing on display ":1.0".

Checking for Deprecated items....
error: This distro (i.e ubuntu 15.04) is either deprecated or not yet supported.
The diagnosis is limited on unsupported platforms. Do you want to continue?(y=yes*, n=no):

Checking for HPLIP updates....
error: Failed to locate hp-upgrade utility

Checking for Dependencies....
warning: ubuntu-15.04 version is not supported. Using ubuntu-14.10 versions dependencies to verify and install...

---------------
| SYSTEM INFO |
---------------

 Kernel: 3.19.0-22-generic #22-Ubuntu SMP Tue Jun 16 17:15:15 UTC 2015 GNU/Linux
 Host: nas
 Proc: 3.19.0-22-generic #22-Ubuntu SMP Tue Jun 16 17:15:15 UTC 2015 GNU/Linux
 Distribution: ubuntu 15.04
 Bitness: 64 bit

-----------------------
| HPLIP CONFIGURATION |
-----------------------

HPLIP-Version: HPLIP 3.15.2
HPLIP-Home: /usr/share/hplip
warning: HPLIP-Installation: Auto installation is not supported for ubuntu distro 15.04 version

Current contents of '/etc/hp/hplip.conf' file:
# hplip.conf. Generated from hplip.conf.in by configure.

[hplip]
version=3.15.2

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/hplip/HP
ppdbase=/usr/share/ppd/hplip
doc=/usr/share/doc/hplip-doc/HTML
html=/usr/share/doc/hplip-3.15.2
icon=no
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/share/cups/drv
bin=/usr/bin

# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
libusb01-build=no
pp-build=yes
gui-build=yes
scanner-build=yes
fax-build=yes
dbus-build=yes
cups11-build=no
doc-build=yes
shadow-build=no
hpijs-install=yes
foomatic-drv-install=yes
foomatic-ppd-install=yes
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=yes
cups-ppd-install=no
internal-tag=3.15.2
restricted-build=no
ui-toolkit=qt4
qt3=no
qt4=yes
policy-kit=yes
lite-build=no
udev_sysfs_rules=no
hpcups-only-build=no
hpijs-only-build=no

Current contents of '/var/lib/hp/hplip.state' file:
Plugins are not installed. Could not access file: No such file or directory

Current contents of '~/.hplip/hplip.conf' file:
[last_used]
device_uri = "hp:/net/Deskjet_6980_series?zc=hp6980"
printer_name =
working_dir = .

[settings]
systray_visible = 0
systray_messages = 0

[commands]
scan = /usr/bin/xsane -V %SANE_URI%

[refresh]
rate = 30
enable = false
type = 1

[polling]
enable = false
interval = 5
device_list =

[fax]
voice_phone =
email_address =

[upgrade]
notify_upgrade = false
last_upgraded_time = 1436446072
pending_upgrade_time = 0

[installation]
date_time = 07/09/15 14:18:48
version = 3.15.2

 <Package-name> <Package-Desc> <Required/Optional> <Min-Version> <Installed-Version> <Status> <Comment>

--------------------------
| External Dependencies |
--------------------------

 gs GhostScript - PostScript and PDF language interpreter and previewer REQUIRED 7.05 9.15 OK -
 network network -wget OPTIONAL - 1.16.1 OK -
 dbus DBus - Message bus system REQUIRED - 1.8.12 OK -
 scanimage scanimage - Shell scanning program OPTIONAL 1.0 1.0.24 OK -
 avahi-utils avahi-utils OPTIONAL - 0.6.31 OK -
 cups CUPS - Common Unix Printing System REQUIRED 1.1 2.0.2 OK 'CUPS Scheduler is running'
Xlib: extension "RANDR" missing on display ":1.0".
Xlib: extension "RANDR" missing on display ":1.0".
 xsane xsane - Graphical scanner frontend for SANE OPTIONAL 0.9 0.998 OK -
 policykit PolicyKit - Administrative policy framework OPTIONAL - 0.105 OK -

-------------------------
| General Dependencies |
-------------------------

 libjpeg libjpeg - JPEG library REQUIRED - - OK -
 libpthread libpthread - POSIX threads library REQUIRED - b'2.21' OK -
 python3-pil PIL - Python Imaging Library (required for commandline scanning with hp-scan) OPTIONAL - 1.1.7 OK -
 libcrypto libcrypto - OpenSSL cryptographic library REQUIRED - 1.0.1 OK -
 libnetsnmp-devel libnetsnmp-devel - SNMP networking library development files REQUIRED 5.0.9 5.7.2 OK -
 python3-pyqt4 PyQt 4- Qt interface for Python (for Qt version 4.x) REQUIRED 4.0 4.11.3 OK -
 sane SANE - Scanning library REQUIRED - 1.0.24 OK -
 python3-xml Python XML libraries REQUIRED - 2.1.0 OK -
 python3-dbus Python DBus - Python bindings for DBus REQUIRED 0.80.0 1.2.0 OK -
 libusb libusb - USB library REQUIRED - 1.0 OK -
 error: python3-reportlab Reportlab - PDF library for Python OPTIONAL 2.0 3.1.44 MISSING 'python3-reportlab needs to be installed'
 cups-image CUPS image - CUPS image development files REQUIRED - 2.0.2 OK -
 python3-pyqt4-dbus PyQt 4 DBus - DBus Support for PyQt4 OPTIONAL 4.0 4.11.3 OK -
 sane-devel SANE - Scanning library development files REQUIRED - 1.0.24 OK -
 cups-devel CUPS devel- Common Unix Printing System development files REQUIRED - 2.0.2 OK -
 python3X Python 2.2 or greater - Python programming language REQUIRED 2.2 2.7.9 OK -
 python3-notify2 Python libnotify - Python bindings for the libnotify Desktop notifications OPTIONAL - - OK -
 python3-devel Python devel - Python development files REQUIRED 2.2 2.7.9 OK -

---------------
| COMPILEDEP |
---------------

 gcc gcc - GNU Project C and C++ Compiler REQUIRED - 4.9.2 OK -
 error: libtool libtool - Library building support services REQUIRED - - MISSING 'libtool needs to be installed'
 make make - GNU make utility to maintain groups of programs REQUIRED 3.0 4.0 OK -

----------------------
| Python Extentions |
----------------------

 cupsext CUPS-Extension REQUIRED - 3.15.2 OK -
 hpmudext IO-Extension REQUIRED - 3.15.2 OK -

-----------------------
| Scan Configuration |
-----------------------

'/etc/sane.d/dll.d/hpaio' not found.
 hpaio HPLIP-SANE-Backend REQUIRED - 3.15.2 OK 'hpaio found in /etc/sane.d/dll.conf'
 scanext Scan-SANE-Extension REQUIRED - 3.15.2 OK -

-----------------------
| Other Dependencies |
-----------------------

------------------------------
| DISCOVERED SCANNER DEVICES |
------------------------------

No Scanner found.

--------------------------
| DISCOVERED USB DEVICES |
--------------------------

No devices found.

---------------------------------
| INSTALLED CUPS PRINTER QUEUES |
---------------------------------

lpstat
------
Type: Unknown
Device URI: No destinations added.

--------------
| PERMISSION |
--------------

Missing Required Dependencies
-----------------------------
error: 'libtool' package is missing/incompatible

ENTER SUDO PASSWORD
-------------------
Please enter the sudoer (steve)'s password:
Do you want to update repository and Install missing/incompatible packages. (a=install all*, c=custom_install, s=skip):a
A package manager '/usr/sbin/dnsmasq -x' appears to be running. Please quit the package manager and press enter to continue (i=ignore, r=retry*, f=force, q=quit) :i
warning: Ignoring running package manager. Some package operations may fail.
Updating repository
-------------------
cmd =sudo dpkg --configure -a
cmd =sudo apt-get install --yes --force-yes -f
cmd =sudo apt-get update
Installing Missing/Incompatible packages
----------------------------------------
cmd =sudo apt-get install --assume-yes libtool

Checking Permissions....
Permissions are correct.

Checking for Configured Queues....
No Queue added

warning: No Queue(s) configured.

Checking for HP Properitery Plugin's....
No plug-in printers are configured.

Diagnose completed...

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