The "promo code" must be activated before 12/31/2021 directly within the Confluent Cloud billing interface. Once activated, the promo value will be available for consumption for 90 days, beginning on the date of activation. Promo value will automatically be applied to any usage charges incurred after activation. Any unused promo value on the expiration date will be forfeited. If you receive an invalid promo code error when trying to activate a code, this means that all promo codes have already been claimed.