Check your server error logs first. You should also enable SMTP debugging to help debug mail issues. To enable, enable the "Enable Email Debugging" option on the
email settings page
on the 'Options' tab. The log should be written to the "logs" folder.
If you are having issues sending email over SSL, this is nothing to do with this software or the mail system used by this software. Most likely
your server's SSL is installed incorrectly. If you have issues, you can disable SSL checking (in favour of always allowing insecure connections) by
changing the "SSL/TLS Only - Do Not Verify Certificates" option on the
email settings page
on the 'Options' tab.
Setting this to 'yes' will allow insecure connections. Whilst this is a workaround, it is NOT recommended.