Update Get-MailTrafficATPReport.md

Author: dariomws

exchange/exchange-ps/exchange/Get-MailTrafficATPReport.md

@@ -184,6 +184,8 @@ Email phish EventTypes:
 
 - Anti-spoof: external ___domain (Indicates an external message caught by anti-phish spoof protection.)
 
+- Dmarc (Indicates a message for which the sender was marked as not authenticated by DMARC.)
+
 - Domain impersonation\* (Indicates a message impersonating a ___domain protected by an anti-phish policy.)
 
 - User impersonation\* (Indicates a message impersonating a user protected by an anti-phish policy.)