Testing the appointment calendar


I setup this website at the start of this year and the booking system is to go live very soon. However, I have forgotten quite a lot about working with Appointments+ and MarketPress, so I need some help.

Firstly, I have tested the booking system here: http://containment.zone/store/products/booking/ and it did seem to work. I got a confirmation email (as the buyer). However, when I then refreshed the booking page, the slot I had booked was still displaying as ‘available’. Is this because I checked out using a PayPal sandbox account?