Hey
@Babouchka! There can definitely be times when a host shows as online in Fleet because it has checked in recently, but has since gone offline and isn't returning a response to a query. The "Errors" tab there would only show data if the host responded to the query with an error message.
If you aren't seeing any errors in the UI or the Fleet server logs, you can check the host's osquery logs to see if there are any issues fetching queries or sending responses. If you're using fleetd,
here's where you'd find those on the host.