If a customer's card fails an automatic payment two times the card will be removed and will need to be replaced with a new card and the customer's series will need to be expired and a new series will need to be purchased using the new card.
If a card has not been removed you can attempt to charge the card again by navigating to;
Admin > Reporting > Series Reporting > Contracts
From there you can scroll down and see all of your failed billing. The cog icon next to each entry will allow you to try to take payment again or open those customers' cards on file. If the billing goes through on the first or second attempt the failed billing 'count' will be reset to zero.
Furthermore, these entries give you the reason the gateway failed the payment as well as the Gateway Transaction ID that will assist you in troubleshooting payment issues with your payment gateway.
It is advised that you check with your payment gateway in regards to specific reasons for failed billing before reaching out to support.
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