The error occurs due to $ value rounding. It is not always possible to sync PO as Orders due to $ value rounding. WMS use $ value rounding for some Items and creates extra (negative value) line when posting to MYOB. MYOB does not support negatives values and that is why PO Order converts to Alert. Datapel suggest to post all Closed Purchase Orders as BILL.
- Ensure the Replicate purchase is set to BILL and not ORDER under Tools>Preferences>Replication> 'Post order to MYOB as " BILL" .
- Ensure the PO doesn't have negative line .