HP Color Laser MFP 178nwg not found?

Why does hp-setup did not find my HP Color Laser MFP 178nwg (while the HP ENVY 5330 is detected well)? Despite "manual discovery" it reports:

HPLIP cannot detect printers in your network.
This may be due to existing firewall settings blocking the required ports. When you are in a trusted network environment, you may open the ports for network services like mdns and slp in the firewall. For detailed steps follow the link. http://hplipopensource.com/node/374

# lsb-release -a
LSB Version: n/a
Distributor ID: openSUSE
Description: openSUSE Leap 15.1
Release: 15.1
Codename: n/a

# hp-check -t
Saving output in log file: /root/hp-check.log

HP Linux Imaging and Printing System (ver. 3.18.6)
Dependency/Version Check Utility ver. 15.1

Copyright (c) 2001-15 HP 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: hp-check can be run in three modes:
1. Compile-time check mode (-c or --compile): Use this mode before compiling the HPLIP supplied tarball (.tar.gz or .run) to determine if the proper dependencies are installed to successfully compile HPLIP.
2. Run-time check mode (-r or --run): Use this mode to determine if a distro supplied package (.deb, .rpm, etc) or an already built HPLIP supplied tarball has the proper dependencies installed to successfully run.
3. Both compile- and run-time check mode (-b or --both) (Default): This mode will check both of the above cases (both compile- and run-time dependencies).

Check types:
a. EXTERNALDEP - External Dependencies
b. GENERALDEP - General Dependencies (required both at compile and run time)
c. COMPILEDEP - Compile time Dependencies
d. [All are run-time checks]
PYEXT SCANCONF QUEUES PERMISSION

Status Types:
    OK
    MISSING - Missing Dependency or Permission or Plug-in
    INCOMPAT - Incompatible dependency-version or Plugin-version

warning: 3-15.1 version is not supported. Using 3-42.3 versions dependencies to verify and install...

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

 Kernel: 4.12.14-lp151.28.48-default #1 SMP Fri Apr 17 05:38:36 UTC 2020 (18849d1) GNU/Linux
 Host: recycler
 Proc: 4.12.14-lp151.28.48-default #1 SMP Fri Apr 17 05:38:36 UTC 2020 (18849d1) GNU/Linux
 Distribution: 3 15.1
 Bitness: 64 bit

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

HPLIP-Version: HPLIP 3.18.6
HPLIP-Home: /usr/share/hplip
warning: HPLIP-Installation: Auto installation is not supported for 3 distro 15.1 version

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

[hplip]
version=3.18.6

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/cups/model/manufacturer-PPDs/hplip
ppdbase=/usr/share/cups/model/manufacturer-PPDs
doc=/usr/share/doc/packages/hplip
html==/usr/share/doc/packages/hplip
icon=/usr/share/applications
cupsbackend=/usr/lib/cups/backend
cupsfilter=/usr/lib/cups/filter
drv=/usr/lib/cups/driver
bin=/usr/bin
apparmor=/etc/apparmor.d
# Following values are determined at configure time and cannot be changed.
[configure]
network-build=yes
libusb01-build=no
pp-build=no
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=no
foomatic-ppd-install=yes
foomatic-rip-hplip-install=no
hpcups-install=yes
cups-drv-install=no
cups-ppd-install=yes
internal-tag=3.18.6
restricted-build=no
ui-toolkit=qt5
qt3=no
qt4=no
qt5=yes
policy-kit=no
lite-build=no
udev_sysfs_rules=no
hpcups-only-build=no
hpijs-only-build=no
apparmor_build=no
class-driver=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:
warning: Could not access file: No such file or directory
 <Package-name> <Package-Desc> <Required/Optional> <Min-Version> <Installed-Version> <Status> <Comment>

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

 cups CUPS - Common Unix Printing System REQUIRED 1.1 2.2.7 OK 'CUPS Scheduler is running'
 gs GhostScript - PostScript and PDF language interpreter and previewer REQUIRED 7.05 9.52 OK -
 xsane xsane - Graphical scanner frontend for SANE OPTIONAL 0.9 0.999 OK -
 scanimage scanimage - Shell scanning program OPTIONAL 1.0 1.0.27 OK -
 dbus DBus - Message bus system REQUIRED - 1.12.2 OK -
 policykit PolicyKit - Administrative policy framework OPTIONAL - 0.114 OK -
 network network -wget OPTIONAL - 1.20.3 OK -
 avahi-utils avahi-utils OPTIONAL - 0.7 OK -

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

 libjpeg libjpeg - JPEG library REQUIRED - - OK -
 cups-devel CUPS devel- Common Unix Printing System development files REQUIRED - 2.2.7 OK -
 cups-image CUPS image - CUPS image development files REQUIRED - 2.2.7 OK -
 libpthread libpthread - POSIX threads library REQUIRED - b'2.26' OK -
 libusb libusb - USB library REQUIRED - 1.0 OK -
 sane SANE - Scanning library REQUIRED - 1.0.27 OK -
 sane-devel SANE - Scanning library development files REQUIRED - 1.0.27 OK -
 libnetsnmp-devel libnetsnmp-devel - SNMP networking library development files REQUIRED 5.0.9 5.7.3 OK -
 libcrypto libcrypto - OpenSSL cryptographic library REQUIRED - 1.1.0 OK -
 python3X Python 2.2 or greater - Python programming language REQUIRED 2.2 3.6.10 OK -
 python3-notify2 Python libnotify - Python bindings for the libnotify Desktop notifications OPTIONAL - - OK -
 python3-pyqt4-dbus PyQt 4 DBus - DBus Support for PyQt4 OPTIONAL 4.0 4.12.1 OK -
 python3-pyqt4 PyQt 4- Qt interface for Python (for Qt version 4.x) REQUIRED 4.0 4.12.1 OK -
 python3-dbus Python DBus - Python bindings for DBus REQUIRED 0.80.0 1.2.4 OK -
 python3-xml Python XML libraries REQUIRED - 2.2.5 OK -
 python3-devel Python devel - Python development files REQUIRED 2.2 3.6.10 OK -
 python3-pil PIL - Python Imaging Library (required for commandline scanning with hp-scan) OPTIONAL - 1.1.7 OK -
 python3-reportlab Reportlab - PDF library for Python OPTIONAL 2.0 3.4.0 OK -

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

 libtool libtool - Library building support services REQUIRED - 2.4.6 OK -
 gcc gcc - GNU Project C and C++ Compiler REQUIRED - 7.5.0 OK -
 make make - GNU make utility to maintain groups of programs REQUIRED 3.0 4.2.1 OK -

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

 cupsext CUPS-Extension REQUIRED - 3.18.6 OK -
 hpmudext IO-Extension REQUIRED - 3.18.6 OK -

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

 hpaio HPLIP-SANE-Backend REQUIRED - 3.18.6 OK 'hpaio found in /etc/sane.d/dll.conf'
 scanext Scan-SANE-Extension REQUIRED - 3.18.6 OK -

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

device `hpaio:/net/ENVY_5530_series?hostname=printer2.deck2.zone42.org' is a Hewlett-Packard ENVY_5530_series all-in-one

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

No devices found.

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

ENVY_5530
---------
Type: Printer
Device URI: hp:/net/ENVY_5530_series?hostname=printer2.deck2.zone42.org
PPD: /etc/cups/ppd/ENVY_5530.ppd
PPD Description: HP Envy 5530 Series, hpcups 3.18.6
Printer status: printer ENVY_5530 is idle. enabled since Wed May 20 20:05:42 2020
Communication status: Good

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

-----------
| SUMMARY |
-----------

Missing Required Dependencies
-----------------------------
None

Missing Optional Dependencies
-----------------------------
None

Total Errors: 0
Total Warnings: 1

Done.