Enhanced status code

SMTP error X.6.5

Conversion failed

Updated Jul 1, 2026

The short answer

Conversion failed Common cause: Required message conversion was unsuccessful

Quick fix

Change content format or fix the conversion gateway

This code is written X.6.5 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

Change content format or fix the conversion gateway

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.6.6 Message content not available
All SMTP error codes
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