Item is restricted and the supplier is not on the Approved Supplier List, or the supplier status ass

Hello

Without putting promise Date (which is not mandatory field)..it gives a Note , Also when user try to put the date afterwards...it does not allow user to put the Promise Date...

after putting promise date when user going to approve PO it gives below error

"Item is restricted and the supplier is not on the Approved Supplier List, or the supplier status assigned to this supplier does not allow PO approval".