I had an issue with my provider where any mail leaving the server requires a specific SMTP server so mails generated from zenphoto goes to limbo. I finally fixed that by modifying the zp_mail function in functions.php with PHPMailer.
So for those of you that want to select a specific SMTP, S/MIME or authentication, I'd suggest looking into incorporating PHPMailer with your installation!
http://sourceforge.net/projects/phpmailerhttp://phpmailer.codeworxtech.com/Oh I'm using an old customized version of zp (1.1.5) so please correct me if the latest zenphoto already has this built in!
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