Why is my email bouncing with a ’550 Relay Not Permitted’ error?

If you are seeing ‘550 Relay Not Permitted’ as an error message in bounce-back responses you receive, there can be a number of reasons why this is happening.

Often, this happens because the nameservers have been changed to make the domain work with our servers, but the domain itself has not been transferred in. Due to the time it takes for domains to propagate across the Internet, there can be a brief period where some remote mail servers direct mail according to the new MX records, but the local mail server is still seeing the old MX records.

This resolves itself once the domain is fully transferred and the new DNS information has completely made its way across the Internet.

You may also have this error due to your mail client not using authentication for your outgoing mail server.  Please make certain that you have set your Outgoing Mail Server to be authenticated by password.

If your ISP has blocked sending mail on Port 25, this error can also occur. You can set your Outgoing Mail Server to Port 587, and this should be a working alternative.

Also, if you are sending an email to a forwarding email, it may be on an infinite loop, where the email it forwards to then forwards back to the first email.  If this is the case, either you or the person you are attempting to get in touch with will need to change where the forwarding email is directed.  Remember, you can set an auto-responding email to forward, and if your auto-responding email is forwarding to the wrong address, it can create this loop.

If you are still having difficulty working out why the 550 error is occurring, please raise a Support Ticket with our Customer Services team.