I am using Amazon Simple Email Service (SES) but after trying several combinations for the url (using tls://, ssl://, and leaving empty), I'm using port 465 and it works for other applications on my server using SES. I get a server error when trying a test of the feedback form (and notifications don't get sent when using the site). Is anybody using SES and successfully using it as an SMTP server.
Just a note that I don't have sendmail or phpmailer installed on my server as I'm using an external smtp server for all my sites. I want to avoid installing phpmailer but is it necessary for this script? I looked at the classes and it does instantiate a phpmailer class but am using the smtp portion of it.