client/write or administrator/write OAuth scope.ACTIVE, in AUD, with last_iteration 0. Unknown body properties are rejected with 400.NON_RECURRING the debit is due from starts_at. For every other frequency the first debit is due one period AFTER starts_at, and each later debit one period after the previous debit's date. Example: a MONTHLY mandate starting 1 March allows its first debit from 1 April. Set starts_at one period before the first collection date. NON_RECURRING does not itself cap the count; set max_iterations to 1 for a one-off debit.