As of Date is the date entered when creating new products, enabling tracking quantity for that product as of this date. You can't create a transaction dated earlier than any product's As of Date on that transaction.
To resolve this you can:
- Change the tracking quantity start date on the product in QuickBooks, to make it earlier than the date of the transaction.
OR - Another solution is to make the product inactive in QuickBooks, change As of date in Mobius integration to a date earlier than the transaction date, rebatch the PO.