VLPOD Overdelivery is not allowing to post. T. Code VLPOD

Hello, experts.

Have problem with over delivery during VLPOD.

VLPOD is not allowing to do the Over Delivery Qty.

Step to perform:

1. Purchase Order

2. Outbound Delivery (NLI2 type)

3. PGI (68A moment type)

4. VLPOD.

Face with the error M7 021 Deficit of Sales order st. blkd 2,000 KG : 26015506 4100 1911198268 T

Please give some advice.