550 5.7.2: Mailing List Expansion Prohibited
The 550 5.7.2 SMTP error means sending to a mailing list is not permitted from your address. Learn what causes this and how to resolve it.
Published · Last verified · Maintained by TamingDNS
550
5.7.2
Mailing List Expansion Prohibited
Common
🔢 Enhanced Status Code Breakdown: 5.7.2
| Component | Value | Meaning |
|---|---|---|
| Class | 5 | Permanent failure (Hard bounce) |
| Subject | 7 | Security or policy |
| Detail | 2 | Mailing List Expansion Prohibited |
Per RFC 3463 Enhanced Mail System Status Codes. Class (X) = severity, Subject (Y) = category, Detail (Z) = specific condition.
💬 What This Error Means
You are not permitted to send to this mailing list or distribution group. The list has restrictions on who can post to it.
Common Causes
- The mailing list only accepts messages from approved senders or moderators
- Your address is not subscribed to the list
- The list has closed or members-only posting policy
How to Fix This
- Subscribe to the mailing list before sending to it
- Contact the list owner to request posting permissions
- If this is a company distribution list, contact your IT admin
📚 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 5.7.2 Mailing list expansion is disallowed
🔗 Related Error Codes
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