NSM won't send emails

I am trying to set up Notification in and I can't get it to work. I'm testing it by trying to send a two factor email for a user and I get "Internal Server Error" every time. Our exchange administrator never sees anything from the NSM server.

NSM 2.3.2-R12-H3 Soniccore Build (6.5.0-616) in a Closed network.

Microsoft Exchange server on the same network.

In Notifications

Mail Server (name or IP address) - IP of my exchange server

From E-mail address - Notification@NSM.com (dummy address)

Advanced settings are turned off.

In Log & Events

Time2022-02-15 10:29:09

CategoryNotification

Log LevelError

MessageSending TFA Token failed.

Message Time2022-02-15 10:29:09

Additional Log Data{"Certificate":{"Raw":"MIIDdzCCAl+gAwIBAgITMAAAA5S+.......(removed the certificate string to save space) ["http://vsrv060ca.ssd.fsi.com/CertEnroll/srv060ls.crl"],"PolicyIdentifiers":null},"Host":"10.253.54.105"}

Source IPNA

Tenant NameGlobal Default Tenant

User NameSystem

User RoleSystem

Request Idaeb08ebc-4915-4bff-bd26-1f5906f31b44

servicealertAndNotificationManager