This feature is enabled automatically, whereas any subscription that fails billing, will automatically be retried in the next billing cycle 3 days and 7 days after it first fails. If the payment is successful on the 3 days after attempt, their subscription will be reactivated and they will be setup for the next billing schedule. If they are unable to auto re-bill after 7 days, you should reach out to the member.
This feature was designed to minimize the need for manual check-ins with your members. When their billing fails (if you have it enabled) we will send them an e-mail to reactivate their account. Now if they fail to do this within 3 days, the system willl attempt again and will send a 2nd e-mail. Lastly if the 2nd attempt fails, we will retry 7 days after the first fail (4 days later) to process the payment.
You can see your subscriptions live by going to the Subscriptions button on the main menu or under Sell. You can levearge the filters to determine who will be charged during the next billing cycle.

Along with filtering out who failed the 3 attempts.
