F5 EM not sending alerts to a Distribution-list.

I am facing a strange behaviour on the F5 EM virtual appliance ver 3.0. I have configured under device-alerts for the EM to send email alerts when any of the monitored devices state changes, like - active to standy and reverse and so on...While testing this, .When i put my email id under the alerts section, i recieve an alert, which means the EM is configured properly for SMTP. BUT when I use a distribution-list (DL) and my self-email is included in that DL , I do not recieve any alerts.

If I send a test email from outlook to that DL, we all recieve that email, which proves that the DL is working.

Any suggestions?