Xfce notification daemon doesn't start

This Xubuntu installation is just a few days old and the daemon apparently worked on the machine (notifications were shown on screen) when booted from the installation medium. After the permanent installation and update i got no notifications on screen. When I open Settings, it shows the following message: "The notification service is not running. No notifications will be shown."

I tried querying systemd about it and got the following:

...% systemctl --user status xfce4-notifyd
● xfce4-notifyd.service - XFCE notifications service
     Loaded: error (Reason: Unit xfce4-notifyd.service failed to load properly: File exists.)
     Active: inactive (dead)

May 21 17:15:21 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:15:32 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:15:32 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:17:01 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:17:01 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:17:01 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:25:34 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:41:38 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:41:50 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
May 21 17:42:29 arny-HP-ProBook-650-G1 systemd[2076]: xfce4-notifyd.service: Two services allocated for the same bus name org.freedesktop.Notifications, refusing operation.
...%

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xfce4-notifyd 0.4.4-1
ProcVersionSignature: Ubuntu 5.4.0-31.35-generic 5.4.34
Uname: Linux 5.4.0-31-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Thu May 21 17:45:11 2020
InstallationDate: Installed on 2020-05-18 (2 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: xfce4-notifyd
UpgradeStatus: No upgrade log present (probably fresh install)