Systemd Journal
The issue
The Supervisor needs access to the systemd journal to access logs of individual system components and apps (formerly known as add-ons). These logs are limited or not available at all if the journal is not accessible.
The solution
The systemd-journal-gatewayd service needs to be running on the host
and exposed to supervisor via unix socket.
If using Home Assistant OS, update to version 7 or later.
If using Home Assistant Supervised, run the following on the host:
sudo apt install systemd-journal-remote -y
and then reboot your system
If after upgrading you are still facing this error, reinstall systemd-journal-remote with the following command
sudo apt-get install --reinstall systemd-journal-remote
and reboot your system
If you still see this issue then run the supervised installer on the host as the supervisor service may need an update as well.