There is an invalid reference to QuickBooks AR Account `Accounts Receivable` in the Invoice. QuickBooks error message- Unknown Error.

This error occurs if you try to export invoices to an account that has not been set for accepting those invoices.

For example, you have two different accounts set up for your Canadian and US clients, you would have to first export the Canadian Invoices and then go to QuickBooks - Setup - Export Tab - change the account receivable to reflect the US invoices and then export again.