The net adjustment amount is not a positive amount and has therefore been rejected.
This error occurs for one of two reasons:
You submit an adjustment amount that exceeds the balance on the order item.
Your adjustment amount is zero.
You can use the Manage Orders feature in Seller Central to determine the outstanding balance
for an order item.
To resolve this error, submit an adjustment amount greater than zero that does not exceed the
outstanding balance for the order item.
Note: Unlike product data, you should not submit adjustment data for an order item multiple
times unless you wish to make multiple adjustments. This error often occurs after resubmitting
an entire adjustment file or feed that contained some errors without first removing the data
that was successfully processed.