If you are using Proofpoint, Barracuda Networks, or other third party inbound email protection services, also add our IP Ranges to your Spam Filter Allow List.
See the following articles for more details on this:
Smarsh uses SPF, DKIM, and DMARC technologies to ensure our mail can be successfully delivered, and to prevent spoofing of smarsh.com as a sender. We encourage you to implement these technologies and verify the legitimacy of all incoming email.