We require to maintain supplier validty check and block he supplier after the certificate is expired.
Supplier should be completly blocked at purchaser level and company level. System should not allow to create PO, GRN and MIRO. As per SAP standard we have used the certificate and assigned it to the supplier but even after the certificate is expired system is allowing to do transaction for that supplier.
Even after the expiry of certificate system is allowing to create PO for this particular supplier.