Hi Errico,
It actually depends on the event's privacy itself. If an event is invite-only, it will not be viewable in the listing. If the event belogs to an invite-only group, it also won't be available in the event listing.
If you are still unable to view events that does not fit the description above, can you provide us access to your backend(/administrator redirects to frontend) and specify which event so I can check the reason you are unable to see those events? Thanks.