Enhanced status code

SMTP error X.6.9

UTF-8 header cannot be transferred

Updated Jul 1, 2026

The short answer

UTF-8 header cannot be transferred Common cause: One or more recipients cannot receive the SMTPUTF8 message

Quick fix

Use compatible recipient infrastructure or ASCII headers

This code is written X.6.9 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

Use compatible recipient infrastructure or ASCII headers

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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