Prorated billing isn't allowed for subscriptions with allowances

{
  "error": {
    "type": "request_error",
    "code": "subscription_prorated_billing_not_allowed_for_allowance",
    "detail": "This subscription has a recurring item where the price has allowances, so prorated_immediately and prorated_next_billing_period aren't allowed as a proration_billing_mode.",
    "documentation_url": "https://developer.paddle.com/errors/subscriptions/subscription_prorated_billing_not_allowed_for_allowance"
  },
  "meta": {
    "request_id": "00000000-0000-0000-0000-000000000000"
  }
}

Details

Status code

400

Error code

subscription_prorated_billing_not_allowed_for_allowance

Error message

This subscription has a recurring item where the price has allowances, so prorated_immediately and prorated_next_billing_period aren't allowed as a proration_billing_mode.

Common causes

• The request sets proration_billing_mode to prorated_immediately or prorated_next_billing_period, and the subscription has an item whose price has allowances.
• Your integration sends the same prorated proration_billing_mode for every subscription update, including updates to subscriptions with items whose price has allowances.

Troubleshooting

• Set proration_billing_mode to full_immediately, full_next_billing_period, or do_not_bill.
• Check whether a subscription has items whose price has allowances before choosing a proration_billing_mode for an update.
• Remove allowances from the price, then try your request again.