In article <01PM4F4PRI4U0000AQ(_at_)mauve(_dot_)mrochek(_dot_)com> you write:
Ah, I didn't look hard enough! In 3463, there's
X.6.3 Conversion required but not supported
The message content must be converted in order to be forwarded
but such conversion is not possible or is not practical by a
host in the forwarding path. This condition may result when an
ESMTP gateway supports 8bit transport but is not able to
downgrade the message to 7 bit as required for the next hop.
which seems about right.
For not being able to deliver an SMTPUTF8 message to a particular mailbox?
Nope, this is for not being able to deliver BINARYMIME. Amazingly, the
line in this thread still matches the topic.
My bad. Yes, I'd say that 5.6.3 is the appropriate code for that, since
a conversion is definitely possible.
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