You cannot set the number of Credits for a membership option to zero. Credits in Clava act as a quantifiable token that your customers use to "pay" for bookings (classes, services, or facility access).
If you need to create a free or unlimited access membership option, you should use one of the following methods instead:
For Unlimited Access: Set the number of unlimited and ensure the membership is configured to auto-renew if it's a subscription. The below example show a Monthly recurring subscription with a 'Gold' Pricing option with both pass credits (entry) and Session credits (classes etc) set to unlimited.
For Free Access (One-off or Limited Use):
Set the credit value to 1.
Set the Price of the membership to £0.00 (or your local currency). Your customers will receive one credit for free and can book one activity that costs 1 credit.
Tip: If you are trying to give someone free access to everything without limiting their bookings, setting a very high credit limit is the standard Clava practice for 'unlimited' memberships.