systemctl inaccessible when enabling DynamicUser=true

[Nils Kattenbeck <nilskemail@xxxxxxxxx>]

Hello,

I am writing a simple oneshot service which should read access from
the journal and systemctl status. To restrict the service I was trying
to enable DynamicUser (and added '
SupplementaryGroups=systemd-journal'). However, the service is unable
to access unit status information and errors with the message: "Failed
to get properties: Transport endpoint is not connected". The error
message is not really helpful what exactly this transport endpoint is.
What parts of sandboxing do I have to disable again to get this
working?
This is systemd 252 on Debian.

Kind regards, Nils