Hey Daniel 👋 After checking with our team, they've informed us that there may be two potential issues here:
1) It might be that we cannot send payments to it, because it's a non-SEPA IBAN.
2) The IBAN may not be sanitized - for it to work with our API, it needs to be in all caps and without spaces.
If you have any further questions or need more help, feel free to reach out to us at apipartner@bunq.com 📩