Managing email servers for Web hosts, VPS hosts, etc, and resolving the issues related to it are a major chunk of the Server Management Services that we offer at Bobcares. We receive a number of email-related support requests as a part of it.

To fix SMTP error 541:Mail rejected by destination domain is one among them. This error in general means that the receiver end blocked the message user sent to them. At times users wonder what triggered it.

Today, let’s discuss the top reasons behind the mail error 541 and it fixes.

ERROR: 541 5.4.1 Mail rejected by destination domain

The bounce-back message on a recent support request that we received looks like:

Most commonly the SMTP 541 error indicates that a spam filter at the recipient end classified the mail as spam. Let discuss the possible reasons behind this behavior:

• Message resembling spam
• Spamming in the server
• IP blacklist/ poor reputation
• False-positive spam triggering at recipient spam filter

Message resembling spam

At times, the recipient’s spam filter blocks emails on the basis that the content resembles spam. This mail block is often triggered by something detected in your email content, but can also be your reply-to address or brand name that has a poor reputation.

Following tips, in general, can help you from tagging emails as spam:

1. Avoid using a purchased bulk email list: Emails sent to an unknown email address is less likely to be opened by the receiver and is more likely to be tagged as spam. Also, these mailing lists in most cases are not maintained properly and may contain a greater number of unused or non-existent email addresses. It also increases the chances of IP blacklist.
2. Avoid using spam-like words/language: Spam filters analyze the emails based on the language. More use of exclamations and all caps title triggers the spam tag easily. Also, provide proper alt-text to the images.

Additionally, it is a good idea to use third-party tools like the one here to generate the spam score of the emails.

Spamming in the server

If you are receiving several bounce backs with “SMTP error 541” all of a sudden, its time to check the email queue of the server. With cPanel or Directadmin control panels, go for the command below:

exim -bpc

This command prints the size of the exim mail queue. A higher number in the result indicates a greater chance of ongoing spamming. Next, using the mail delivery report in WHM can provide an overview of the emails sent from the server.

We already have a couple of articles on identifying spamming and its mitigation. You can have a look at them here.

IP blacklist/ poor reputation

At times ongoing spamming may not be the culprit of the error message. It could be related to a previous one. The blacklist of mail server IP address of the domain could lead to rejection of mails at the receiver end.

We also have a few posts that discuss the IP blacklists and its removal procedures in detail.

False-positive spam triggering at recipient spam filter

Rarely, you may also find the emails blocked even though everything is fine at the sender’s side. This could be a false positive trigger by the receiver’s spam filter or a very vigorous spam filter rule.

You could whitelist your domain at the receiver’s spam filter to avoid the mails from getting rejected.

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Conclusion

To conclude the SMTP error 541 indicates emails are rejected by the receiver. It could be due to reasons ranging from an ongoing spamming to a false positive spam trigger at receivers spam filter. Also, we discussed the methodologies that our Support Engineers follow in each scenario to fix the error.