Enhanced status code

SMTP error X.6.10

Deprecated

Updated Jul 1, 2026

The short answer

Deprecated Common cause: Duplicate of X.6.8

Quick fix

Treat as X.6.8

This code is written X.6.10 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

Treat as X.6.8

Related codes

X.6.0 Other or undefined media error X.6.1 Media not supported X.6.2 Conversion required and prohibited X.6.3 Conversion required but unsupported X.6.4 Conversion with loss performed X.6.5 Conversion failed
All SMTP error codes
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