What will happen if a transaction is declined for SCA?

For any declined MIT (merchant initiated transaction) transactions, we will use the same flow (including webhooks, transaction/invoice states) that is used for dunning - since in both cases, customer action to get back in good standing is required.

A new email specific to SCA will be sent in lieu of the payment declined email. This email will include a link to a new Edit Billing Info URL that will have a user go through SCA.

Our documentation at https://docs.recurly.com/docs/dunning-management goes into detail on the flows.