The email transaction has failed permanently. This catch-all permanent error is used when the server rejects the message for reasons including spam detection, content policy violations, IP blacklisting, authentication failures, or general policy blocks.
What Does Error 554 Mean?
SMTP code 554 is a general-purpose permanent failure code indicating the entire mail transaction has failed. It is one of the most serious bounce codes because it often indicates a fundamental problem with the sender's reputation or the message content rather than a simple address issue.
Providers use 554 for their most severe rejections. Gmail returns 554 for messages that fail content scanning or are detected as spam or malware. Microsoft returns 554 5.7.1 when your IP is on their blocklist or the message is classified as spam. Yahoo returns 554 for permanent reputation blocks. Unlike 550 (which is usually address-specific), a 554 often means the entire sending domain or IP is being rejected.
If you receive 554 errors across multiple recipients at the same provider, it almost certainly indicates a sender reputation issue. Check your IP against blacklists, verify your authentication records, and review your sending practices. This requires immediate attention.
Common Causes
- Sending IP is blacklisted by the receiving provider
- Message content detected as spam or contains malware
- Severe authentication failure (no SPF, no DKIM, DMARC reject)
- Domain or IP has extremely poor sender reputation
- Content policy violation (phishing, malware, prohibited content)
- Connection rejected at greeting (before any commands)
How to Fix Error 554
- Check your IP against all major blacklists using a Blacklist Checker immediately
- Verify SPF, DKIM, and DMARC records are correctly configured
- Review your sender reputation using Google Postmaster Tools and Microsoft SNDS
- Clean your email list of invalid addresses and spam traps
- Review and improve your email content to avoid spam triggers
- If IP is blacklisted, follow the removal process for each blacklist
Frequently Asked Questions
SMTP error 554 means the email transaction has permanently failed and the receiving server will not accept the message. This is a hard bounce indicating a general permanent rejection, often caused by blacklisting of the sender's IP or domain, spam content detection, failed email authentication (SPF/DKIM/DMARC), or security policy violations on the recipient's server. The 554 code is a catch-all permanent failure that is frequently used by major providers like Gmail, Microsoft, and Yahoo when blocking suspicious senders.
The "554 5.7.1 message blocked" error means the recipient's server has rejected your email due to a specific security or anti-spam policy violation. This sub-code (5.7.1) explicitly indicates that the content of your message was flagged as spam, your sending IP is on a blocklist, or your email lacks proper authentication. Microsoft/Outlook and Yahoo commonly return this code when blocking emails that contain suspicious links, excessive capital letters, or other spam-like characteristics.
You should not immediately resend the same email after a 554 error, because the server will reject it again for the same reason. First, you must identify and fix the root cause: check if your IP or domain is blacklisted using MXToolbox, verify your SPF/DKIM/DMARC records, review your email content for spam triggers, and confirm the recipient address is valid. Only after resolving the underlying issue should you attempt to resend. If the recipient's server was temporarily down (rare for 554), you may retry after a few hours.
Both 554 and 550 are permanent (5xx) hard bounce errors, but they indicate different types of rejection. A 550 error usually points to a specific identifiable problem such as a non-existent recipient address or a policy violation tied to the recipient. A 554 error is a broader, more generic permanent rejection often related to sender reputation, IP blacklisting, spam content, or overall policy-based blocking. In practice, 554 is the most commonly used code for hard blocks by major email providers.
To fix a 554 rejection due to security policies, take these steps: (1) check your sending IP and domain against major blacklists like Spamhaus, SORBS, and Barracuda using MXToolbox; (2) verify that your SPF, DKIM, and DMARC records are correctly configured and aligned; (3) review your email content for spam indicators like excessive links, all-caps text, or suspicious attachments; (4) ensure your sending volume has not spiked suddenly. If blocked by a specific provider, follow their postmaster guidelines -- Google (postmaster.google.com), Microsoft (sender.office.com), and Yahoo (senders.yahooinc.com) each provide sender support tools.