Feeds - Upload invoices for FBA shipments which require the shipmentid sent along

as per error message in the developer guide https://m.media-amazon.com/images/G/03/B2B/invoice-uploader-developer-documentation.pdf

InvoiceFileIsNotPDF: o When it occurs: When the uploaded document is anything other than PDF. o Description in feed result: Invoice uploaded is not pdf for shipmentId {shipmentId}, orderId {orderId} and InvoiceNumber {invoiceNumber} o Error Code: 79503

the metadata string I tried and received this error, although 'orderid' was correct and the shipment id confirmed belonging to that order metadata:orderid=123-1231231-1231234;metadata:invoicenumber=475263;metadata:shipmentid=DXHh6Ps3x;metadata:documenttype=Invoice;metadata:transfer-encoding:chunked;data:application/pdf;base64

is the shipmentid key wrong or anything else? did someone resolve the same? I do not use VAT Calculation Service.

Apologies for the late reply here.

That error would appear to occur when the invoice file uploaded is not in PDF format. Unlikely to be a problem with any of the metadata attributes specifically.

Feeds.submit_feed method's feed argument should contain the bytes for a file object containing the Invoice, originally in PDF format. Are you having issues handling the file being uploaded?