Can't sync invoice to archived Xero contact

Created an invoice from a Syncro ticket, for an infrequent customer. Got this message on saving: "The specified contact details matched an archived contact. Archived contacts cannot currently be edited via the API. "

So I restored the Xero contact and tried to resync. Same message. Do I have to re-import this contact from Xero? There is an Import Contacts button on the Xero app page, but I don’t want all my Xero contacts which include many non-customers.

Is there a way to fix using the API? What fields does Syncro use to match Xero contacts to its customers?

@bill1 I’m checking on your account, but our mapping tool that uses the API isn’t finding the customer either. Can you send me a DM with a link to the customer in Xero? We can manually map the customer using that link.