# Invalid update options for items on a trialing subscription

You are attempting to update items on a trialing subscription with invalid options

---

## Example

```json
{
  "error": {
    "type": "request_error",
    "code": "subscription_trialing_items_update_invalid_options",
    "detail": "You can't add or remove items for a subscription in trial, and you must use `do_not_bill` as the `proration_billing_mode` when updating quantities of existing items.",
    "documentation_url": "https://developer.paddle.com/errors/subscriptions/subscription_trialing_items_update_invalid_options"
  },
  "meta": {
    "request_id": "00000000-0000-0000-0000-000000000000"
  }
}
```

## Details

| Attribute | Value |
| --- | --- |
| Status code | 400 |
| Error code | `subscription_trialing_items_update_invalid_options` |
| Error message | You can't add or remove items for a subscription in trial, and you must use `do_not_bill` as the `proration_billing_mode` when updating quantities of existing items. |

## Common causes

- You are trying to update item quantities on a trialing subscription without proration_billing_mode: do_not_bill
- You are trying to add an item to a trialing subscription
- You are trying to remove an item from a trialing subscription

## Common solutions

- Ensure you are using `proration_billing_mode`: `do_not_bill` when updating the item quantity on a subscription that is trialing.