[otrs] agent notification (SMTP sending mail) problem

I am using SMTP to send mail in OTRS. If you go into compose mail, and send an email, it works fine. But notifications to the agent if a ticket is created or replied to do not work. In the system log, it says: Can't send to: pfahy@paradiesanalytics.com! Enable debug for more info! I can't figure out this problem. Everything seems to be setup correctly. Please let me know if you have any idea. Thanks, Paul