One of the reasons for this could be the
date parameters of your Standing Order.
2020-07-30, make sure that the
day_of_monthis set to
30to match your
2. Make sure the
first_payment_date is on a business day. If it falls on a weekend or a bank holiday, the request will fail with
"error_description": "Invalid parameters",
"The first payment date must be a business day"
You can check the calendar of UK Bank Holidays here