I am not sure about monetization of this forum right now and I realize amazon ses will be not cost effect at the moment. Please check SendGrid they provide 100 emails per day without any cost forever.Currently just using my hosts (cPanel).
I haven’t heard of Amazon SES, but I’ll take a look.
I'll look at this shortly!Do you send by php or smtp? To avoid this problem you can use smtp.
You could test the mail against the blacklists.
Otherwise you would have to look which provider the user is using and announce there that you are not sending spam.