What happens when you send an email and it was returned or bounced back to you with a message like: Mail delivery failed: returning message to sender?
Errors like this one are generally encountered when there is an issue on the recipient server, or the intended recipient does not exist on the remote server. It could also be caused by a blacklisted (suspected for spewing spam) server.
The bounce-back message will have this error as the SUBJECT of the email, and the body of the message should contain the original message that it was attempting to be sent. If you know how to review these emails, they will typically tell you what the issue was. For example, the below bounce specifies:
The following address(es) failed: recipient@RemoteDomain.com
As an example, here is an email that was returned to the sender with the headers included.
Example Bounce-Back Message
Return-path: <>
Envelope-to: sender@example.com
Delivery-date: Thu, 4 Nov 2021 16:42:54 -0400
Received: from mailnull by ecbiz103.inmotionhosting.com with local (Exim 4.77)
id 1TRUGT-0005Qd-RT
for sender@example.com; Thu, 4 Nov 2021 16:42:54 -0400
X-Failed-Recipients: recipient@RemoteDomain.com
Auto-Submitted: auto-replied
From: Mail Delivery System <mailer-daemon@ecbiz103.inmotionhosting.com>
To: sender@example.com
Subject: Mail delivery failed: returning message to sender
Message-Id: <e1trugt-0005qd-rt@ecbiz103.inmotionhosting.com>
Date: Thu, 4 Nov 2021 16:42:53 -0400</e1trugt-0005qd-rt@ecbiz103.inmotionhosting.com></mailer-daemon@ecbiz103.inmotionhosting.com> This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed: recipient@RemoteDomain.com
No Such User Here —— This is a copy of the message, including all the headers. —— Return-path: <sender@example.com>
Received: from sender@example.com by ecbiz103.inmotionhosting.com with local (Exim 4.77)
(envelope-from <sender@example.com>)
id 1TRUGT-0005QT-Q5
for recipient@RemoteDomain.com; Thu, 4 Nov 2021 16:42:53 -0400
To: recipient@RemoteDomain.com
Subject: [example.com] Please moderate: “About us”
X-PHP-Script: example.com/wp-comments-post.php for 123.123.123.123
Date: Thu, 4 Nov 2021 20:42:53 +0000
From: WordPress <wordpress@example.com>
Message-ID: <82f2c6cb759fb7e7c03356a25c799790@example.com>
X-Priority: 3
X-Mailer: PHPMailer 5.1 (phpmailer.sourceforge.net)
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=”UTF-8″ A new comment on the post “About us” is waiting for your approval
https://example.com/ Author : Payday loans (IP: 123.123.123.123)
E-mail : payday@spam.com
URL : https://www.paydayspam.com
Comment: Payday loans are available for any occasion!
What Caused this Returned Message?
In the bounce-back example above, the cause of the issue is that this user has WordPress setup to allow comments on posts. A spammer attempted to leave a comment on one of their posts and the WordPress administrator of this site has set up their e-mail account as recipient@RemoteDomain.com. So that is the address used to send comment moderation requests to. However, that e-mail address doesn’t exist on the RemoteDomain.com mail server, so it’s always going to fail and cause a bounce-back error.
Typically, these types of bounce-back errors are hard bounces, meaning that trying to send the message again won’t be successful.
Resolving Mail Delivery Failed: Returning Message to Sender Bounce-Backs
Since these are due to multiple reasons, the solutions can vary. Below are the most common solutions to getting your email delivered successfully:
- Check the spelling of the email address for typos
- Check that the person gave you the correct email address
- Remove special characters from To or Subject field
- Create the email account that is receiving/sending mail (if you host it)
- Make sure your domain did not expire (you can see the expiration in the WHOIS record)
- Ensure your Mail Exchange (MX) records are pointing to the correct mail server
- If you suspect a blacklisting, check with your hosting provider for help
- Enable two factor authentication (TFA)
Since this error can be caused by server issues it can be helpful to ask the person you are sending to if they are having any other related problems.
Source: InMotion
