SMTP Error 554: Transaction Failed (How to Fix It)

Open the bounce notification.

Variations:

554 Transaction failed
554 5.7.1 Message rejected
554 Relay access denied
554 Message refused
554 Permanent failure

The extended 5.x.x code is important.

If another SMTP code appears, refer to our SMTP Error Codes guide.

SMTP 554 usually indicates a permanent block due to:

• Spam policy violation
• Authentication failure
• IP reputation issue
• Relay restrictions
• Message content filtering

Carefully read the extended error message.

If content filtering is suspected:

• Remove excessive links
• Avoid all caps
• Remove suspicious attachments
• Send a plain-text test email

If the test succeeds, content likely triggered the block.

Ensure:

• SMTP authentication is enabled
• SPF record is correct
• DKIM is active
• DMARC (if configured) is valid
• You are using port 465 or 587 with SSL/TLS

Authentication misalignment frequently causes 554 errors.

• Check whether your sending IP is listed on any blocklists
• Confirm reverse DNS (PTR) is configured

It is always recommended to monitor your IP reputation and health regularly.

Log in to:

• cPanel → Email → Track Delivery 
• Plesk → Websites & Domains → Select your domain → Mail → Track Email Delivery 

Confirm:

• Permanent rejection (554)
• Specific policy or spam message returned

Example:

554 Invalid recipient 
554 Sorry, no mailbox here by that name. 
554 No valid recipients

What It Means:
The recipient email address does not exist or is disabled.

How to Fix It:

• Double-check the spelling of the email address
• Confirm the recipient mailbox is active
• Ask the recipient to verify their correct email
• Remove invalid addresses from mailing lists

Reassurance: This does not affect your hosting or mailbox. It only affects this specific message.

Example:

54 5.7.1 Message blocked due to spam content 
554 rejected due to spam content 
554 Spam detected

What It Means:
The receiving server’s spam filter flagged your email content.

Potential Triggers:

• Suspicious links
• Spam-like wording
• Large attachments
• Blacklisted sending IP

How to Fix It:

• Remove shortened or suspicious links
• Reduce excessive formatting or ALL CAPS
• Remove large attachments (or use cloud sharing)
• Scan your website and device for malware
• Run a blacklist check on your sending IP

If sending marketing email, review your list hygiene and sending practices.

Example:

554 <[email protected]>: Relay access denied

What It Means:
Your SMTP authentication is failing or not enabled.

The server does not recognise you as an authorised sender.

How to Fix It:

• Ensure SMTP authentication is enabled
• Use the full email address as username
• Confirm the correct password
• Verify SSL/TLS is enabled
• Confirm the correct SMTP port (465 or 587)

If the password was recently changed, update it on all devices.

Example:

554 Message not accepted for policy reasons

What It Means:
The recipient server rejected the message due to internal security or policy rules.

Common Causes:

• Missing SPF/DKIM
• DMARC enforcement
• IP reputation issues
• Geo-blocking

How to Fix It:

• Verify SPF record is correct
• Confirm DKIM is enabled
• Check DMARC policy settings
• Run a blacklist check
• Contact the recipient’s postmaster if necessary

Advanced users may need DNS adjustments.

What It Means:
Your email exceeds the recipient’s size limit.

How to Fix It:

• Compress attachments
• Use cloud storage instead
• Keep total email size under 20–25MB

Example:

554 Message is not RFC compliant; missing "Date" header 554 Malformed mail denied

What It Means:
The message format violates email protocol standards.

Common Causes:

• Custom scripts
• Misconfigured SMTP libraries
• Incorrect line endings (bare LF instead of CRLF)

How to Fix It:

• Ensure your application uses proper SMTP libraries
• Update your mail script
• Verify headers include Date, From, To, Message-ID
• Check CRLF line endings

Advanced: Developers may need to review the mailer configuration.

Example:

554 rejected due to virus 
554 Virus found, message permanently rejected

What It Means:
The message or attachment triggered antivirus detection.

How to Fix It:

• Scan your device for malware
• Remove suspicious attachments
• Recreate the attachment file
• Verify your website is not compromised

If this repeats, run a full security review.

• Check for permanently rejected vs. deferred messages
• Remove permanently rejected messages if necessary

exim -bp 

postqueue -p

• Misaligned authentication often triggers 554

dig +short TXT example.com # SPF 
dig +short TXT default._domainkey.example.com # DKIM

• Confirm PTR (reverse DNS) records are correct

swaks --to [email protected] --server mx.example.com --data 
"Subject: Test\n\nHello" 
telnet mx.example.com 25

• Use this to confirm your server is accepted by recipient MTA

• Check simultaneous SMTP connections:

netstat -anp | grep :25 
lsof -i :25

• Adjust MTA limits carefully:
  • Exim: smtp_accept_max
  • Postfix: default_process_limit, smtpd_client_connection_count_limit

Yes, this is a permanent error and typically requires action before attempting to resend again.

Not always. The extended error message will confirm this.