If you want to send an email from your server, there are many things to consider. You need a clean configuration so other mail providers do not classify your emails as spam or reject them completely. Sometimes the error messages can be a bit confusing.

If there is a configuration problem, Google might reject your emails with the following error message:

550-5.7.1 [45.145.224.X] The IP you're using to send mail is not authorized to 
550-5.7.1 send email directly to our servers. Please use the SMTP relay at your 
550-5.7.1 service provider instead. For more information, go to

The IP you’re using to send mail is not authorized to send email directly to our servers. Please use the SMTP relay at your service provider instead. For more information, go to …

Why does this error occur?

Google rejects emails sent from IP addresses listed in the Spamhaus database. This is to prevent spam and unwanted emails. This can cause the error message.

How can I fix this problem?

  1. Check your IP address: Go to Spamhaus. Enter your server’s IP address to see if it is listed.
  2. Remove the IP from the list: Follow the instructions on the Spamhaus website to remove your IP address from the database. Usually, removal is immediate.
  3. Use an SMTP relay server: Instead of sending emails directly from your server, configure your mail server to use an SMTP relay server provided by your service provider. This increases the chances of your emails being delivered correctly.

If you have any questions about this topic, you can check Google’s error codes (https://support.google.com/a/answer/3726730?hl=en) or contact our support team.