Please post a few screenshots of your advanced email setup.
I ended up calling support. The adv alert engine did not like:
field DNS is equal to value <server1>
Node Name is equal to <server1>
Thanks for your responses.
I belive we had a similar problem when our virus scan/security program was updated. You may want to check that the outbound traffic on that server through port 25 is working. I will try to find in my notes exactly what are problem was but you may want to take a look at your firewall settings on that machine/sercurity policies.