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If Yahoo mail delivery issues have been bugging you recently, this article is for you! Yahoo has started blocking unauthenticated messages that don’t meet their latest guidelines. When your Yahoo email fails to get delivered, Yahoo may send you an error code. It is crucial to understand what these Yahoo error codes mean, to troubleshoot the error quickly.

What is an SMTP Error Code?

An SMTP error code is a numerical response code sent to indicate the outcome of an email sent through SMTP (Simple Mail Transfer Protocol). SMTP generates codes to communicate the status of mail delivery (success or failure). The error code is usually accompanied by a message that describes the error. This message is usually short, and it explains why the email was rejected or the issue encountered during the transfer.

For example, Yahoo error code 421 can describe a temporary error due to service blockages. ‌Yahoo error code 554 depicts a permanent error due to authentication failures. 

Common Yahoo Error Codes Debunked

Yahoo mail delivery errors can be grouped into 2 categories: temporary errors and permanent errors. In this article, we will be touching base on temporary errors while explaining permanent error codes in detail. 

1. 4XX (421 and 451) Temporary Error Code 

4XX Error Description

Your Yahoo email can be temporarily blocked due to a temporary error. ‌Yahoo error codes 421 and 451 might be sent to you in such a situation. Temporary errors, while won’t lead to outright rejections, can postpone the delivery of your email. 

Reasons for 4XX Temporary Errors

You can receive the 4XX (421 and 451) Yahoo temporary error codes if:

• You keep sending bulk messages from a particular IP, which can potentially spam Yahoo inboxes
• Yahoo has received complaints against your email sending practices from receivers 
• Connection failures, outages, or temporary service unavailability  

How to Fix Yahoo 421 and 451 Errors?

To fix Yahoo’s temporary errors, you can:

1. Enable one-click unsubscribe for your email messages 
2. Make sure you are sending messages that interest your receivers 
3. Not indulge in any suspicious activities 
4. Follow RFC-compliant message formatting 
5. Try sending the email again after some time 

2. 5XX (553 and 554) Permanent Error Code

5XX Error Description

Unlike temporary errors, which may auto-resolve, the 5XX permanent errors may lead to permanent message rejections. Yahoo sends 553 and 554 error codes to depict permanent errors in message delivery. If you come across these error codes, you must take action now!

Reasons for 5XX Permanent Errors 

You can receive the Yahoo 553 and 554 error messages if you:

• Fail to comply with Yahoo’s bulk sender guidelines 
• Your message failed email authentication checks for DMARC, SPF, or DKIM 
• Your bulk messages are unauthenticated (i.e. missing DMARC, SPF and/or DKIM setup)
• Yahoo suspects illegal or suspicious activities originating from your domain 
• Your domain is blocklisted on a popular DNS blocklist like Spamhaus 

There are several other reasons that may trigger the Yahoo 554 error code. The reason can be as simple as sending an email to an address that doesn’t exist! The reason can also be as complex as DMARC failure.

Whatever may be the reason, to prevent email deliverability issues, you must fix it promptly!

How to Fix Yahoo 553 and 554 Error?

If you notice Yahoo 553 and 544 error codes for your message, you can fix them by following these steps:

1. Setup SPF, DKIM, and DMARC for your domain 
2. Monitor your authentication status and deliverability using DMARC reports 
3. Make sure your messages are of value to Yahoo receivers 
4. Make your promotional messages easy to unsubscribe
5. Maintain a low spam rate for your emails and avoid getting blocklisted

Yahoo warns against resending emails which encounter permanent errors like 553 and 544.

You can check out Yahoo’s document here to view the complete list of Yahoo error codes.

Fixing “554 5.7.9 Message Not Accepted for Policy Reasons” Yahoo Error

A permanent Yahoo error message senders ‌frequently face post the Yahoo sender policy updates is the “554 5.7.9 Message Not Accepted for Policy Reasons” error. This may be triggered if your domain lacks (or fails) DMARC authentication.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol. DMARC can help you authenticate your domain name, monitor email delivery, and prevent phishing attacks. Yahoo has asked email senders sending more than 5000 emails per day to configure DMARC for their domains.

Note: Yahoo’s 554 troubleshooting guide explains that your email may be rejected if you are on p=reject while failing DMARC authentication. You can learn more about failure reasons and prevention in our DMARC fail guide.

5 Steps to Fix 554 5.7.9 Yahoo Error

Before proceeding to troubleshoot the error, check if your domain is already DMARC compliant. Use our free domain checker tool.

1. Configure SPF or DKIM

To implement DMARC, you need to have either SPF or DKIM enabled for your domain. Sign up with us for free to set up these protocols in a few minutes!

2. Create a DNS Record for DMARC

Create your DMARC record using our DMARC generator tool.

3. Select a DMARC Policy

While Yahoo supports a minimum DMARC policy of “none”, our experts don’t recommend it. Domain owners should start with a “none” policy with the long-term goal of shifting to “reject”.

4. Upload DMARC Record to DNS

Access your DNS management console to publish your DMARC record. If you don’t have access, contact your domain administrator at once!

5. Monitor Your Email Deliverability

After you have successfully implemented DMARC, it is important to enable DMARC reports. These reports will help you monitor Yahoo mail delivery issues.

Resolve Yahoo Mail Delivery Issues with PowerDMARC

PowerDMARC’s Google and Yahoo Compliance Program has been actively helping businesses around the world meet sender guidelines. If you are struggling with SPF, DKIM, and DMARC implementation – we have got you covered! Our hosted solutions and seasoned experts help you deploy the protocols easily! We also make your DMARC reports easy to read, so you can detect issues quickly.

Thousands of organizations have achieved DMARC compliance with PowerDMARC, and so can you. Get started today!

*** This is a Security Bloggers Network syndicated blog from PowerDMARC authored by Yunes Tarada. Read the original post at: https://powerdmarc.com/smtp-yahoo-error-codes/