Using Phpmailer Results In Many Blocked Emails

I am using PHPmailer; though probably a version from 2012 - I haven't updated it for a while. I am sending mail like this: $mail = new PHPMailer(); $mail -> IsSM

Solution 1:

Well I solved the issue; the code above was not the problem and works great.

In my subject, I used a phrase regarding "verify your account information" and that got it blocked on a few ISP's.

So the lesson is, your subject matters. I was looking at my php code and my body content before I realized this.

Solution 2:

Some other things to note too when dealing with rejected mail:

• The server you are sending mail from matters a lot. Many, like AWS, are blacklisted by default, and you need to request special permission to be able to send mail. Use a blacklist-check if you're not sure.
• Always always create an appropriate SPF txt record for your domain (in DNS). This ensures that the sending server is a verified sender for your domain.
• If you're having troubles sending mail, check the server logs to see why. Many providers (Outlook.com for example) will provide good feedback in the form of an RFC number or even a link to follow for more information.
• When all else fails, use a mail gateway API like SendGrid, Mandrill, or Amazon SNS.