Mutt not sending email

[cssgalactic]

Ok, I have configure getmail to fetch my messages and mutt to read all my fetched messages. I have installed ssmtp and configured mutt, but when i send email i get this error from mutt:

Error sending message, child exited 127 (Exec error.).

here is the ssmtp configuration in /usr/local/etc/ssmtp/ssmtp.conf

MailHub=smtpauth.earthlink.net:587
UseTls=YES
FromLineOverride=YES
Hostname=XX.XXX.XXX.XX
RewriteDomain=earthlink.net
Root=XXXXXX@earthlink.net
AuthUser=XXXXXX@earthlink.net
AuthPass=XXXXX

here is how i'm telling mutt what to use to send mail on ~/.muttrc

set sendmail="/usr/local/etc/ssmtp"

And yes I have disabled sendmail in etc/rc.conf

sendmail_enable="NO"
sendmail_submit_enable="NO"
sendmail_outbound_enable="NO"
sendmail_msp_queue_enable="NO"

What step Am I missing? Please help me configure ssmtp or suggest another solution.

Thanks