If your clients have credits in their account but are still unable to book a class, it might be due to the settings of the Services.
- Business settings > Memberships & Billing > Services.
A common error is to put a one (1) instead of a zero (0) as a minimum amount of credits allowed to book a class.
To avoid this problem, make sure to have a zero within the Minimum credits allowed section. This means that they can leave zero credits in their account.
If you have a one on the Minimum credits allowed, clients will always have to leave one credit in their account.