Check that you have created slots and that there is at least a time slot with:
- at least one day of the week is selected li>
- a start time and end time that are different li>
- associated subarea is the sector (and the deliverer in the PRO version) corresponding to the delivery address, and that at least one day is not checked in time restrictions li>
Also make sure that the booking length is greater than 0.
If you have created at least one availability check that a part of it is on the reservation period.
If you created the unavailability sure it does not completely cover the reservation period.