You can configure the Approved Senders list on the End-User Quarantine console to reduce false-positives for spam detections.
Note:
The Approved Senders list has priority over the Blocked Senders list. If a sender IP address is in both the Blocked Senders list and the Approved Senders list, Deep Discovery Email Inspector does not block messages from the sender.
For more information, see Blocked Senders List.