ALERT EMAIL ERROR for NPM

Hello Anyone out there,

im new to NPM. I've read on the administrationguide that NPM can notify alert through email. I need help anyone out there about this. because when I tried to test the trigger alert. it kept prompting this error message : -

EXCEPTION STACK: -->

The transport failed to connect to the server.

: CDO.Message.1 :    at Interop.cdosys.MessageClass.Send()  

at SolarWinds.Orion.Core.MessageActions.ActionEmail.AsyncMailToSend.SendThis(Object state);