Unable to connect to dbus: Could not connect: Permission denied

[Serhiy]

Two of these warnings appear every time I'm launching Firefox. If I remove `libappmenu-gtk*` they change to a warning that appmenu module cannot be loaded.

I do not see any other D-Bus problems anywhere else. dbus-monitor --session connects succesfully.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: appmenu-gtk3-module 0.7.1-1
ProcVersionSignature: Ubuntu 4.19.0-13.14-generic 4.19.20
Uname: Linux 4.19.0-13-generic x86_64
ApportVersion: 2.20.10-0ubuntu21
Architecture: amd64
CurrentDesktop: KDE
Date: Sun Feb 17 16:56:46 2019
DistributionChannelDescriptor:
 # This is a distribution channel descriptor
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-xenial-amd64-20160624-2
InstallationDate: Installed on 2018-08-09 (192 days ago)
InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47
SourcePackage: appmenu-gtk-module
UpgradeStatus: Upgraded to disco on 2019-01-01 (46 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[oldfred (oldfred)]

Using focal Kubuntu.
Firefox filling .xsession-errors
Has pyqt5 (5.14.1+dfsg-3build1) focal; & current versions of other dbus related files that are standard.

fred@z97-focal-kubuntu:~$ uname -a
Linux z97-focal-kubuntu 5.4.0-58-generic #64-Ubuntu SMP Wed Dec 9 08:16:25 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
fred@z97-focal-kubuntu:~$ echo $DESKTOP_SESSION
plasma
fred@z97-focal-kubuntu:~$ cat /etc/X11/default-display-manager
/usr/bin/sddm
fred@z97-focal-kubuntu:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"
fred@z97-focal-kubuntu:~$ apt show firefox
Package: firefox
Version: 84.0+build3-0ubuntu0.20.04.1

** (/usr/lib/firefox/firefox:112432): WARNING **: 09:37:31.184: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112483): WARNING **: 09:37:31.636: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112515): WARNING **: 09:37:31.830: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112540): WARNING **: 09:37:31.970: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112609): WARNING **: 09:37:33.138: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112734): WARNING **: 09:38:27.515: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112782): WARNING **: 09:38:27.981: Unable to connect to dbus: Could not connect: Permission denied
** (/usr/lib/firefox/firefox:112833): WARNING **: 09:38:28.518: Unable to connect to dbus: Could not connect: Permission denied