550 5.7.1: Message Rejected by Policy

🔢 Enhanced Status Code Breakdown: 5.7.1

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

💬 What This Error Means

Your email was stopped by a security guard. The receiving server has a 'policy rule' that blocked your message. This is a broad error that can mean anything from your IP being on a list of known spammers to your email content looking suspicious.

Common Causes

• Your sending IP address is on a public blocklist
• Your domain authentication (SPF, DKIM, or DMARC) failed or is missing
• Something in your email content triggered a spam filter
• The recipient has specifically blocked your domain or email address

How to Fix This

• Use our Blacklist Checker to see if your IP is currently listed on any major blocks
• Verify your SPF, DKIM, and DMARC records with our Domain Checker
• Review your email for "spammy" words, too many links, or large attachments
• If you're a legitimate sender, try contacting the recipient through another way to ask them to "whitelist" you

📚 Official Documentation

📋 Real-World Example Messages

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

550 5.7.1 [198.51.100.42] The IP you're using to send mail is not authorized to send email directly to our servers.
550 5.7.1 Message rejected due to content restrictions

🔗 Related Error Codes

🔧 Related Diagnostic Tools

These tools can help you diagnose and fix this type of bounce:

🔧 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.