[Xymon] re no email alerts being sent on Macintosh

Hello

We have xymon installed on a Macintosh running 10.6.8. We have configured the alerts conf file as follows; HOST=%(help|host|jumpmail|wilma|portal).jumpit.ca SERVICE=http MAIL (email address)@jumpit.ca REPEAT=20 RECOVERED

When an alert is triggered, no email is being sent out.

I can however send an email from the host command line as follows; sh-3.2# mail (email address)@jumpit.ca Subject: test test message . EOT sh-3.2#