How do I identify POs that have failed communication via fax or email?

Is there an easy way to identify all POs that have failed their communication being sent via email or fax?

For example, if a PO is supposed to be communicated to a supplier via email through EDI but it fails for some reason, how do I know it has failed?

What if many PO communications have failed, how do I see all the POs that have failed with failed date?