Hi
So Sivakumar, did you post that AR Invoice?
Also check this
In order to block negative inventory for each warehouse, the following settings should be made:
1. Go to Administration -> System Initialization -> Document Settings -> General Tab, make sure 'Block Negative Inventory' is checked.
2. Go to Item Master Data -> Inventory tab, make sure 'Manage Inventory by Warehouse' is checked.
how can we block negative inventory ?
Block negative inventory by Item Setting