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Bounce Decoder: 550 5.7.24

SPF, DKIM, DMARC, FCrDNS, Blacklists & Inbox Prediction

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550 5.7.24 — SPF Validation Error (PermError)

The 550 5.7.24 bounce means your SPF record has a permanent error — usually too many DNS lookups or a syntax mistake. Learn how to fix SPF PermError.

🔴
Permanent Failure (Hard Bounce)
SMTP Code
550
Enhanced Code
5.7.24
Category
SPF Validation Error (PermError)
Frequency
Common

🔢 Enhanced Status Code Breakdown: 5.7.24

Component Value Meaning
Class 5 Permanent failure
Subject 7 Security or policy
Detail 24 SPF Validation Error (PermError)

Per RFC 3463 Enhanced Mail System Status Codes. Class (X) = severity, Subject (Y) = category, Detail (Z) = specific condition.

💬 What This Error Means

Your SPF record caused a permanent error during validation. This usually means the record has a syntax error or exceeds the 10 DNS lookup limit defined in RFC 7208.

Common Causes

  • SPF record contains a syntax error
  • More than 10 DNS lookups required (exceeds RFC 7208 limit)
  • Circular or invalid include mechanism

How to Fix This

  • Validate your SPF record syntax with our SPF Checker
  • Count your DNS lookups — if over 10, use SPF macro expansion or flattening
  • Remove any invalid include mechanisms

📋 Real-World Example Messages

These are real bounce message formats you might receive. Paste yours into the Bounce Decoder for instant analysis. 

550 5.7.24 SPF PermError
550 5.7.24 The message was rejected because of SPF PermError: too many DNS lookups

🔗 Related Error Codes

550 5.7.23
SPF Validation Failed
550 5.7.26
DMARC Policy Violation

📚 Official Documentation

↗ RFC 7208 — SPF PermError

🔧 This Bounce Is Related to Email Authentication

Fixing this type of bounce requires correctly configured SPF, DKIM, and DMARC records. Our free Domain Checker analyses all three in one scan and tells you exactly what to fix.

Run a Free Domain Authentication Check →
🔍

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