This is definitely a policy issue, but without recreating the situation on a test network, it is difficult to fix. It could either be a problem getting to the cert file or it could be an issue binding to the ssmtp port (465).
Can you open up a bug report (http://bugs.engardelinux.org/
) and submit all the necessary information for us to reproduce it. Also please include the SELinux policy "permission denied" messages. Thanks.