Prevent order confirmations sent via PHPMailer from ending up in spam

When I send order confirmations via PHPMailer, they usually end up in spam folders of Google, Yahoo and Hotmail and also take a long time to deliver. Is there a checklist or something of things I should be aware of when sending confirmations this way? Mail from most sites that I order from or register to gets delivered instantly and doesn't ge开发者_运维百科t flagged as spam. What do they know that I don't?

There are tons of reasons why email could end up in spam. Try to put more information in the body of the email. Mentioning users name and surname in email's body or subject also helps. And check if your server isn't black listed http://www.mxtoolbox.com/blacklists.aspx This happens a lot on shared web hosting. Someone sends out spam, and the whole server gets blacklisted.

This actually isn't caused by PHPMailer, it's caused by the content in the email, the email sent host, or something of that nature that is triggering it to be thought of as spam.=

As Webnet said, it could be the content of the email or the source. For example, my company is hosting a website on Amazon AWS but password and account recovery emails are being flagged as spam. Solution? We used Zend::Mail to connect to and send the emails from a non-AWS host.