[Appointments+] Calendar not showing booking

Hi

A have set up 3 providers, 2 services, and made a appointments page via the checkbox on the settings page.

One service is 30min massage, the other is 60min massage, but when choosing a provider and booking a 30min massage, it does not show up when looking at the calendar for booking 60min massages. Oddly the booked 60min massage showes up on the calendar when booking 30min massages.

What's causing this problem ?

All the best
Carsten