Enhanced status code

SMTP error X.7.2

Mailing list expansion prohibited

Updated Jul 1, 2026

The short answer

Mailing list expansion prohibited Common cause: Sender is not permitted to post to the list

Quick fix

Request permission or use an authorized sender

This code is written X.7.2 because the reason is the same whether the failure is temporary (a 4 first digit) or permanent (a 5). Read the first digit of your own bounce to know which applies.

How to fix it

Request permission or use an authorized sender

Related codes

X.7.0 Other or undefined security status X.7.1 Delivery not authorized X.7.3 Security conversion required but impossible X.7.4 Security features not supported X.7.5 Cryptographic failure X.7.6 Cryptographic algorithm not supported
All SMTP error codes
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