To test the complete paid appointment flow, the event type and its linked checkout product must both be live. Open the event type editor and select Test paid booking in its Payment section.
The test opens the booking page in test mode. Choose a time, complete the form and pay with the Mollie test method shown by checkout. Check that the booking and payment both appear as test activity, not as a real appointment sale.
If the test button is unavailable, save your event type first and check that both it and the linked product are live. A regular checkout product test only checks the payment flow; it does not hold or confirm an appointment slot.