Popup Notifications not working (error screenshot added)[SOLVED]

Popup Notifications stopped working one day after installing Ubuntu Mate 18.04.2. If I open the Popup Notification settings and click "preview" I get the error in the screenshot with all themes. Any help?

I'll suggest to reinstall related packages with

sudo apt-get install --reinstall mate-notification-daemon-common
sudo apt-get install --reinstall mate-notification-daemon

and retry.

That did not work, but thank you for the suggestion.

until you get a better reply can you run command between # lines
################################
cat /var/log/syslog | grep dbus > /tmp/dbus.txt
###############################
As a normal (non-root) user you can then open txt file with Pluma and select entire contents then paste to link below and I chose 24 hour expiry but maybe for you choose longer?
https://paste.ubuntu.com/
and my example
https://paste.ubuntu.com/p/WpYk4vBZPR/

Then change command to
#################
cat /var/log/syslog | grep freedesktop > /tmp/free.txt
##################################
I get at least one hit of interest to me,
Jul 27 12:15:02 um notification-ar[2252]: GBus.Error:org.freedesktop.DBus.GLib.ErrorError: Method invoked for RegisterStatusNotifierHost returned FALSE but did not set error

And just curious....Can you try UM v 19.04, if our replies do not help?

https://paste.ubuntu.com/p/52WhxwTtjf/
https://paste.ubuntu.com/p/JDwDnG5qMK/

Yikes I can not see any failures for your pastes

Try disabling all notifications and then re-enable as per post

How do I do that? I don't see an enable/disable option anywhere.

edit: I tried the commands in that topic, but they didn't fix the issue.

I tried installing Notification apps from other DEs but no luck.

Hi

Notification apps from other DEs

that is not expected work....the notification daemons or clients expect a certain environment to interact with. for example XFCE has a notification daemon. But there are some standalones as per
https://wiki.archlinux.org/index.php/Desktop_notifications

ok well until you get a better reply.....what software/hardware detection changes do you need as a notification.

eg you have a laptop and go to a different wifi network area?
Or maybe some kind of bluetooth audio?
I have a tower so not fussed either way if notifications do not show.
but I do see the safe to remove notification when I "eject" usb media in Caja

I can see several that relate to specific hardware or software as seen by command

apt search notification | less

I'm not getting any notifications but I mostly miss browser and Discord notifications.

Ok that web chat has alternative software not sure what web browser you are using or why you need a notification.....thats just me being old not a negative ok?
but for a different web chat app.....I have used notification type messaging when I am not marked myself away....and gone to another web page instead of waiting for action on web chat.....so I agree web chat notification is important to me too.

so....if you have not deleted them....use root powers to view your logs for the install and apt....I prefer

sudo mc /var/log

or

sudo caja /var/log

##################
I do not want to ask you to upload your logs as there too many of them
Instead view each.....and post snippets of each that you think might show
either an error or something you think might be removed that relates to
either dbus......icons....images....fonts

While you are waiting for a reply (or better suggestion) keep a copy of the logs you are not too sure about it.

Additionally....post install ......Did you have to do any config setup for your locale?
And, have you noticed any other strange behaviour in your software
--I think a test for dbus might be to wifi networking

I found this:
Jul 25 19:56:02 ubuntu-mate dbus-daemon[1540]: [session uid=999 pid=1540] Activating service name='org.freedesktop.Notifications' requested by ':1.17' (uid=999 pid=1592 comm="nm-applet " label="unconfined")
Jul 25 19:56:02 ubuntu-mate org.freedesktop.Notifications[1540]: Unable to init server: Could not connect: Connection refused
Jul 25 19:56:02 ubuntu-mate mate-notificati[1770]: cannot open display:
Jul 25 19:56:02 ubuntu-mate dbus-daemon[1540]: [session uid=999 pid=1540] Activated service 'org.freedesktop.Notifications' failed: Process org.freedesktop.Notifications exited with status 1
Jul 25 19:56:02 ubuntu-mate dbus-daemon[1540]: [session uid=999 pid=1540] Activating service name='org.freedesktop.Notifications' requested by ':1.17' (uid=999 pid=1592 comm="nm-applet " label="unconfined")
Jul 25 19:56:02 ubuntu-mate org.freedesktop.Notifications[1540]: Unable to init server: Could not connect: Connection refused
Jul 25 19:56:02 ubuntu-mate mate-notificati[1772]: cannot open display:
Jul 25 19:56:02 ubuntu-mate dbus-daemon[1540]: [session uid=999 pid=1540] Activated service 'org.freedesktop.Notifications' failed: Process org.freedesktop.Notifications exited with status 1

Hi
which log are they from?
Do they repeat for today's date?
Can you remember if that date and that time is when AFTER notifications stopped working?
According to my preferences you posted on Jul 27 so its not clear to me if these are the culprits.....or the only culprits

that's from /var/log/installer/syslog
I will check other logs

OK from my syslog search I get hit for org.freedesktop.Notifications
Aug 1 10:54:06 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications'

from installer log for me not OP I get
Jul 10 08:34:47 ubuntu-mate dbus-daemon[1928]: [session uid=999 pid=1928] Activating service name='org.freedesktop.Notifications' requested by ':1.0' (uid=999 pid=1927 comm="/usr/bin/fcitx -d " label="unconfined")
Jul 10 08:34:47 ubuntu-mate ModemManager[1227]: Couldn't check support for device '/sys/devices/pci0000:00/0000:00:1c.0/0000:01:00.0': not supported by any plugin
Jul 10 08:34:47 ubuntu-mate org.freedesktop.Notifications[1928]: Unable to init server: Could not connect: Connection refused
Jul 10 08:34:47 ubuntu-mate mate-notificati[1943]: cannot open display:
Jul 10 08:34:47 ubuntu-mate dbus-daemon[1928]: [session uid=999 pid=1928] Activated service 'org.freedesktop.Notifications' failed: Process org.freedesktop.Notifications exited with status 1

the log only has entries from July 25th for some reason.
is there a command to start or enable org.freedesktop.Notifications ?

I can't find a log called installer, just a directory called installer

sorry

/var/log/installer/syslog
/var/log/syslog is what I meant

todays log is what I am interested in

for me

cat syslog | grep org.freedesktop.Notifications
Aug 1 10:44:42 um dbus-daemon[1358]: [session uid=1000 pid=1358] Activating service name='org.freedesktop.Notifications' requested by ':1.24' (uid=1000 pid=1615 comm="caja " label="unconfined")
Aug 1 10:44:42 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications'
Aug 1 10:49:13 um dbus-daemon[1358]: [session uid=1000 pid=1358] Activating service name='org.freedesktop.Notifications' requested by ':1.24' (uid=1000 pid=1615 comm="caja " label="unconfined")
Aug 1 10:49:13 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications'
Aug 1 10:52:47 um dbus-daemon[1358]: [session uid=1000 pid=1358] Activating service name='org.freedesktop.Notifications' requested by ':1.24' (uid=1000 pid=1615 comm="caja " label="unconfined")
Aug 1 10:52:47 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications'
Aug 1 10:54:06 um dbus-daemon[1358]: [session uid=1000 pid=1358] Activating service name='org.freedesktop.Notifications' requested by ':1.24' (uid=1000 pid=1615 comm="caja " label="unconfined")
Aug 1 10:54:06 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications'
Aug 1 11:01:36 um dbus-daemon[1358]: [session uid=1000 pid=1358] Activating service name='org.freedesktop.Notifications' requested by ':1.24' (uid=1000 pid=1615 comm="caja " label="unconfined")
Aug 1 11:01:36 um dbus-daemon[1358]: [session uid=1000 pid=1358] Successfully activated service 'org.freedesktop.Notifications

found this on /var/log/syslog

Jul 31 01:43:17 geets-PC dbus-daemon[1255]: [session uid=1000 pid=1255] Activating service name='org.freedesktop.Notifications' requested by ':1.5613' (uid=1000 pid=5821 comm="/usr/share/discord/Discord " label="unconfined")
Jul 31 01:43:17 geets-PC deepin-notifica[17350]: Unable to locate theme engine in module_path: "adwaita",
Jul 31 01:43:17 geets-PC deepin-notifica[17350]: Unable to locate theme engine in module_path: "adwaita",
Jul 31 01:43:17 geets-PC org.freedesktop.Notifications[1255]: database open
Jul 31 01:43:17 geets-PC dbus-daemon[1255]: [session uid=1000 pid=1255] Successfully activated service 'org.freedesktop.Notifications'