ubuntu 20.4. update-manager: “Settings & Livepatch” not starting and returning error

[cprecht2123]

Bug:
ubuntu update-manager Updates work perfectly, but when trying to open “Settings & Livepatch” the following error is returned in the terminal and “Settings & Livepatch” does not open.

ERROR:dbus.proxies:Introspect error on :1.172:/: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoReply: Message recipient disconnected from message bus without replying
Traceback (most recent call last):
  File "/usr/bin/software-properties-gtk", line 100, in <module>
    app = SoftwarePropertiesGtk(datadir=options.data_dir, options=options, file=file)
  File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 211, in __init__
    self.backend.Reload();
  File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 72, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/python3/dist-packages/dbus/proxies.py", line 141, in __call__
    return self._connection.call_blocking(self._named_service,
  File "/usr/lib/python3/dist-packages/dbus/connection.py", line 652, in call_blocking
    reply_message = self.send_message_with_reply_and_block(
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.ServiceUnknown: The name :1.172 was not provided by any .service files

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: update-manager 1:20.04.10.1
ProcVersionSignature: Ubuntu 5.4.0-51.56-generic 5.4.65
Uname: Linux 5.4.0-51-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Thu Oct 15 16:51:11 2020
InstallationDate: Installed on 2020-10-09 (5 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[cprecht2123 (cprecht2123)]

It appears that the actual issue does not relate to the "update-manager", but more to the package "software-properties-gtk", which should start when clicking “Settings & Livepatch”. I created a bu report accordingly here, provided I am correct:
https://bugs.launchpad.net/ubuntu/+source/software-properties/+bug/1900098