ISSUE ON UNDER DELIVERY WHEN CONFIRMATION

Hi SAP EXPERTS,

dear all, i have one issue regarding under delivery ,i have used opk4  ERROR WHEN QUANTITY FALLS BELOW UNDER DELIVERY TOLERANCE.

THEN I I HAVE CREATE PRODUCTION ORDER IN CO01, AFTER THAT C011N FOR CONFIRMATION ,BUT IT STILL DID NOT  WORKS,

PLEASE GET ME OUT

THANKS