550 5.1.2: Bad Destination Domain

The 550 5.1.2 error means the recipient domain has no working mail servers. Learn the causes and how to fix this SMTP bounce.

Published · Last verified · Maintained by TamingDNS

🔴
Permanent Failure (Hard Bounce)
SMTP Code
550
Enhanced Code
5.1.2
Category
Bad Destination Domain
Frequency
Common

🔢 Enhanced Status Code Breakdown: 5.1.2

Component Value Meaning
Class 5 Permanent failure (Hard bounce)
Subject 1 Address / Destination
Detail 2 Bad Destination Domain

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

💬 What This Error Means

The 'domain' part of the address (everything after the @) is wrong. Either the domain doesn't exist, or it doesn't have any mail servers set up to receive messages. It's like trying to send a letter to a city that isn't on the map.

Common Causes

  • A typo in the domain name (like @gmial.com instead of @gmail.com)
  • The company's domain has expired or been taken down
  • The domain is real, but they haven't set up their "MX records" to receive email yet

How to Fix This

  • Carefully check the spelling of the domain name
  • Use our Domain Checker to see if the domain has working mail servers
  • If it's your own domain, check your DNS settings to make sure your MX records are active

📚 Official Documentation

RFC 3463: Enhanced Status Codes

📋 Real-World Example Messages

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

550 5.1.2 Bad destination mailbox address
550 5.1.2 <[email protected]>: Recipient address rejected: Domain not found
🔍

Got a bounce message to decode?

Paste your full NDR email, SMTP error line, or mail log fragment to get an instant plain-English diagnosis.

Open the Bounce Decoder →