External tax mode only allowed for partial refunds

{
  "error": {
    "type": "request_error",
    "code": "adjustment_tax_mode_not_allowed",
    "detail": "You can only use `tax_mode: external` when `type` is `partial` and `action` is `refund`.",
    "documentation_url": "https://developer.paddle.com/errors/adjustments/adjustment_tax_mode_not_allowed"
  },
  "meta": {
    "request_id": "00000000-0000-0000-0000-000000000000"
  }
}

Details

Status code

400

Error code

adjustment_tax_mode_not_allowed

Error message

You can only use `tax_mode: external` when `type` is `partial` and `action` is `refund`.

Common causes

• You're trying to create an adjustment with tax_mode: external, but type is full. External tax mode is only supported for partial refunds.
• You're trying to create an adjustment with tax_mode: external, but action isn't refund. External tax mode is only supported for refund adjustments.

Troubleshooting

• Make sure type is partial and action is refund when using tax_mode: external.
• Use tax_mode: internal to specify that amounts are inclusive of tax.