Set the conflict rule on a booking link
What counts as busy. It decides whether a tentative meeting or an all-day event blocks a slot.
"Busy" is less obvious than it sounds. Is a tentative meeting busy? An invitation you declined but never deleted? An all-day birthday entry? Each of those is a real calendar entry and each could reasonably block or not block a booking.
The conflict rule is where you decide, and the two entries that catch people are all-day events — which can silently block an entire day — and declined invitations, which may still sit in your calendar depending on your settings.

Steps
Find the conflict rule on the booking link
It sits with hosts, availability and the caps, because all four narrow the same thing: what the invitee is offered.
Of the four, this is the one whose effect is least visible, because it depends on what happens to be in your calendar rather than on a number you set.
Decide what "busy" means for you
Confirmed meetings only, or anything in the calendar including tentative ones. Stricter means fewer double bookings and fewer available slots.
Watch out for all-day events
A birthday, a public holiday entry, a "working from home" marker. If any of these are marked busy, they can block a whole day and you will not immediately see why.
Watch out for declined invitations
Meetings you declined may still sit in your calendar. Whether they block depends on this rule and on your calendar settings.
Test against a messy week
One with a tentative meeting, an all-day event and something you declined. An empty calendar tests nothing at all.
Recheck when a whole day goes missing
If a booking link is offering nothing on a day you know you are free, an all-day event marked busy is the first thing to look for.
Check it worked
Add an all-day event to tomorrow and check whether the link still offers slots. Whatever happens is what will happen on your birthday, and it is better to find out now.
The parts people get wrong
- The AI voice agent respects the same rule, so it cannot offer a slot the booking link would refuse.
- A conflict rule that is too loose produces double bookings; one that is too strict produces a link that looks broken. Test both directions.