missing_billing_email

The invoice has no billing email and its customer has no email, so there is nowhere to send it.

HTTP status400
Error typeinvalid_request_error
RetryNo. Fix the request.

What to do

Set an email on the customer.

Response shape

{
  "error": {
    "type": "invalid_request_error",
    "code": "missing_billing_email",
    "message": "…",
    "doc_url": "https://docs.borga.is/errors/missing_billing_email",
    "request_id": "req_…"
  }
}

See all error codes and how to handle them.