Enhanced status code Permanent

SMTP error X.5.2

Syntax error

Updated Jul 1, 2026

The short answer

Syntax error Common cause: SMTP command syntax could not be parsed

Quick fix

Correct the malformed SMTP command

5 - Permanent. The server will not try again. Fix the cause before you resend.
This code is written X.5.2 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

Correct the malformed SMTP command

Related codes

X.5.0 Other or undefined protocol status X.5.1 Invalid command X.5.3 Too many recipients X.5.4 Invalid command arguments X.5.5 Wrong protocol version X.5.6 Authentication exchange line too long
All SMTP error codes
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