pipewire-media-session question

I have pipewire installed and activated it for my user via

systemctl enable --user pipewire
systemctl enable --user pipewire-pulse
systemctl enable --user pipewire-media-session

Sound is working in the different programs : vlc, amarok, firefox, etc

Now when I see in journalctl one error

philippe@hpprol2:~> systemctl status --user pipewire-media-session
● pipewire-media-session.service - Multimedia Service Session Manager
     Loaded: loaded (/usr/lib/systemd/user/pipewire-media-session.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2021-06-08 08:28:19 CEST; 3min 5s ago
   Main PID: 11126 (pipewire-media-)
      Tasks: 2 (limit: 4915)
     Memory: 3.1M
        CPU: 178ms
     CGroup: /user.slice/user-1000.slice/user@1000.service/session.slice/pipewire-media-session.service
             └─11126 /usr/bin/pipewire-media-session

juin 08 08:28:19 hpprol2 systemd[2536]: Started Multimedia Service Session Manager.
juin 08 08:28:32 hpprol2 pipewire-media-session[11126]: GetManagedObjects() failed: org.freedesktop.DBus.Error.TimedOut

is this an error or a warning?
How can I solve this?

Many thanks in advance

I used to get this error right after I setup pipewire.

> journalctl | grep 'GetManagedObjects.. failed'
May 24 12:13:58 Mobile-PC pipewire-media-session[1888]: GetManagedObjects() failed: org.freedesktop.systemd1.NoSuchUnit
May 24 12:21:32 Mobile-PC pipewire-media-session[1903]: GetManagedObjects() failed: org.freedesktop.systemd1.NoSuchUnit
May 24 12:30:48 Mobile-PC pipewire-media-session[1878]: GetManagedObjects() failed: org.freedesktop.systemd1.NoSuchUnit

Looking at my history file, I see that I enabled bluetooth to get rid of it.

> history | grep '2021-05-24'
15075  2021-05-24 14:24:44 systemctl enable --now bluetooth

You may have a different service disabled, but it appears that there are some hard coded checks in pipewire-media-session that will fail if certain services are disabled.