UDM Pro Security Detections - Synology Mailplus Server

So I use Synology Mailplus server for email service (no relay service, straight from NAS). Everything is running smoothly, but, have a concern about the security detections logged by my UDM Pro. All the detections are incoming connections to my Synology NAS, and nothing else. At first, I got worried and started blocking all these IPs and ended up blocking email service. So I unblocked the IPs and email service was restored. Figured out that every time email comes in, it is flagged by my UDM Pro as a security issue. I turned off security notifications on my UDM Pro as they were too many coming in. I would like to turn on notifications at some point but was wondering if there is way for my UDM to trust these incoming connections to my NAS for mailplus service. Any thoughts?