If a payment fails, a member's account is in 'overdue' status for approximately a week, during which time they will not be able to access content unless otherwise configured as noted here: Overdue Access Configuration. After that week of being 'overdue', if they haven't updated billing information or restarted their account, it will be canceled and they will not have access to any associated protected content. Once that member signs back up on the same account by purchasing that subscription again, their account is reactivated and they will "speed up and unlock access" even though they have not been able to log in. The clock keeps ticking during the time they've been canceled. For example, if the account was canceled at Week 1 and reactivated at Week 3, the member will have access to content from Week 1, 2 and 3 after reactivating their account.
You do have the option of manually changing a member's place in the drip content schedule. For more specifics about how to do that, you can review the article Change the Member's Place in a Drip Content Schedule. If you need to change the member's place in a drip content schedule once a member reactivates their membership, you can set up a push notification to alert you by changing the following headings: event, membership status changed and active.