Issue:
During exporting of your proposal you are seeing the following error message and the proposal doesn’t appear in Quickbooks.
Resolution:
You will see this error message if you attempt to export an invoice into Quickbooks that has already been exported. This is intentional and designed to prevent duplicate invoices in Quickbooks.
You can search inside of Quickbooks for a previous invoice if you need to view it.
NOTE: In previous versions, it was allowed to export the same proposal multiple times by adding a suffix to it.