Viktor Dukhovni:
> On Fri, Aug 28, 2015 at 05:59:08PM +0200, Per olof Ljungmark wrote:
>
> > Yes, that helped with Thunderbird but not from Horde/IMP where it still
> > bounces the same way.
> >
> > The difference seems to be that IMP sends a
> > "Content-Transfer-Encoding: quoted-printable"
> >
> > and TB
> > "Content-Transfer-Encoding: 8bit"
> >
> > Could this be the cause?
>
> Yes, if IMP sends data claimed to be quoted-printable, but contaning
> unencoded non-ASCII characters.
>
> You'll need to capture a sample message and find the violation.
Postfix will reject violations with "strict_8bitmime = yes", with
the caveat that this is not recommended for a general-purpose mail
server.
You could also log a warning with a header or body check
that matches /[^[:ascii:]]/.
Wietse
