Im struggling to get the API to create an invoice when sending the purchase reference over. If I remove the following <PurchaseReference>XXXXXXX</PurchaseReference>
it goes through fine? Am I doing something wrong?
.........<Currency>GBP</Currency>
<TermDays>1</TermDays>
<Language>en</Language>
<SingleInvoiceData>
<IssueDate>' . date('Y-m-d', time()) . '</IssueDate>
<PurchaseReference>XXXXXXX</PurchaseReference>
</SingleInvoiceData>
<InvoiceLines>
<ItemLines>.........