The following are possible reasons why you may not be able to purchase a Gold Pass.
1. You have already purchased a Gold Pass.
Only one Gold Pass may be purchased per Apple ID/Google Account per save data. If multiple family members are using the same Apple ID or Google Account and one of them has already purchased a Gold Pass, other family members will not be able to purchase a Gold Pass. In this situation, another Apple ID or Google Account would need to be used.
If a Gold Pass has been canceled but has not expired yet, a new Gold Pass cannot be purchased until that pass has expired.
2. Purchasing is restricted.
If credit card usage is restricted or parental controls that restrict making purchases have been implemented, then a purchase cannot be made.
Please check that there are no problems with the payment method.