Connex will skip adding duplicate invoices to QuickBooks. If Connex finds a matching invoice for the payment and the invoice has a balance, then Connex will insert a payment.
What field in Authorize.NET should match the QuickBooks order number field?
In Authorize.NET, each transaction has a field called invoice number. Entering an invoice number is optional. In the event the invoice number is empty, Connex uses the transaction ID as the QuickBooks order number. Therefore, the invoice number field must match an existing order in QuickBooks.
Here is a printed receipt from an Authorize.NET transaction:
Here is a matching invoice in QuickBooks:
How do I set-up the integration?
On the my connections page of Connex , set up the connection with your ordering system. At the configure page, select invoices only from the first drop down. At the complete page, click my connections and add a new connection for Authorize.NET. Select invoices payments if paid from the first drop down. Your Authorize.net connection will find the invoice and skipping adding it, then it will find the payment to that invoice number and apply the payment.