on a website I use PHPMailer to send automated registration emails, etc and also a newsletter-tool (which loops through the emails and sends them one by one).

Also, I configured in Gmail under Settings and confirmed @mydomain addresses, so I can send from @mydomain emails without the gmail address being displayed.

Furthermore I authorized the website to send mails with this link: https://accounts.google.com/DisplayUnlockCaptcha

Now, after 2 month where everything worked perfectly fine, suddenly users started not to receive emails anymore and most recently emails are not even being sent anymore.

Also, I received many error messages like this:

Technical details of permanent failure:

Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 5.4.1 [email protected]: Recipient address rejected: Access Denied (state 13).

When I check at this link: https://toolbox.googleapps.com/apps/checkmx/

It tells 2 none critical errors:

  • Relayhost configuration detected.
  • There SHOULD be a valid SPF record.

So, the questions I would have were:

  • does anybody have any hint why it stopped working, what the error messages mean?
  • what to do to fix it?
  • where do I set a SPF record (Cpanel?)?
  • what is a relayhost and how to fix that?

It is about 1000-1400 mails a day (gmail's limit is 2000). Also, what can I do wrong when setting up an SPF record? I've heard there are some testing tools for that.

Thank you so much already in advance for your help!

  • 2
    Check mxtoolbox.com to make sure your IP/domain was not inadvertently blacklisted as spam Nov 13, 2012 at 17:01
  • @joshuahedlund: thank you, that's a great tool! my domain is not listed, luckily...
    – Chris
    Nov 13, 2012 at 17:11

1 Answer 1


This would appear to be due to the emails being detected being sent as a relaay instead of from a correctly configured SMTP server. The best option is to configure your PHP.ini file to use SMTP and to use your gmail server for SMTP and then use the PHP mail() function to avoid this error in the future.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.