While troubleshooting Symantec Protection Engine (SPE) for Network Attached Storage (NAS) you need to enable NetApp's ONTAP Antivirus Connector Logging.
For the most up to date information on enabling the ONTAP Antivirus Connector logging please see Netapp's technical documentation at https://kb.netapp.com/onprem/ontap/da/NAS/How_to_enable_ONTAP_Antivirus_Connector_Logging