This error typically occurs when the PO linked to the invoice in sync error has been modified in QuickBooks.
In other words, if a receipt has already been generated for the PO (attached to the invoice in sync error) in QuickBooks, the sync error will appear on the invoice.
To solve the sync error:
Open QuickBooks
Launch QuickBooks on your computer.
Log in using your credentials.
Search for the PO Number associated with the invoice
Use the search bar or navigate to the appropriate section (e.g., Purchase Orders) to find the PO number.
Check for Receipts
Once you find the PO, check if there are any receipts associated with the PO. This can usually be done by viewing the details of the PO.
Delete the Receipt
If you find any receipts, select and delete them as per the QuickBooks interface options (usually found under options like 'More' or right-clicking on the receipt).
Switch to ProcureDesk
Open ProcureDesk on your computer and log in using your credentials.
Go to Actions
Navigate and open the invoice in ProcureDesk.
Click on 'Actions.'
In the 'Actions' menu, select Send for Integration.
Run the Web Connector and the invoice should now be synced to QuickBooks.