P4310 Commodity Code has an invalid data dictionary value

When I try to update a PO in P4310 it shows:"Commodity Code has an invalid data dictionary value. "  and "Invalid Commodity Code "

But Commodity Code is blank in this item and blank is in the UDC.

And when i place the order those error didn't come out. only when I try to update PO it shows error.

Could anyone tell me where should i check for this error?

it's a new Environment.