Where to setup PO mail delivery Failure to sender

 Hi All ,

I have supplier " XXX" , and created the PO using the supplier information . And PO sent for Approvals .

The PO had approved by all approvers and it is send a  " PO PDF to the Supplier" notification using workflow to the supplier email address .

If the supplier email address is valid then it is fine , it is directly sent to the suppliers .

If the supplier email address is invalid then it has send  Failure notification to the one sender .

Where to setup that sender details ????