Many banks (Itaú, Santander, Caixa) don't support Pix codes without a reference. To fix set a dummy reference of "***" when none is set (this is what Santander bank does when generating Pix codes without a reference). Again thanks to INGO for testing. opw-3818534 closes odoo/odoo#158713 Signed-off-by: Josse Colpaert <jco@odoo.com>