To see why an invoice is not synced, the first step is to check your Products/Services and confirm that all of them are synced. If any are not, this may be because they share the same name in QuickBooks, which prevents them from syncing properly. Once that’s corrected, you can go back to the invoice and try syncing it manually from the bottom of the invoice page. That should allow the sync to go through successfully
This is How a Product/Service Not Synced Would Look Like
