Are you seeing this page?
You will see this page if the owner of the bookable calendar you are trying to access has turned the sharing off.
When the sharing link is 'off' the calendar is private to the owner and nobody else can see it. To publish the calendar the owner needs to turn the sharing link 'on'.
If you think that the calendar is 'off' by mistake, please contact the owner to turn it on. Then you would be able to see their availability and book a meeting.