Ever figure this out? I have the same issue. I tried using ISY's alert account with gmail and it worked which leads me to believe it is a Verizon setting issue. But i've checked 25 times and they look correct:
smtp server: outgoing.verizon.net
SMTP Port: 25
user id: dwgtx
password: *********
Timeout 10,000
Use TLS (tired both on / off)