> On Jul 11, 2016, at 9:27 AM, Rick Zeman <rze...@gmail.com> wrote:
>
> Explicitly filtering in:
>
> smtp_sasl_mechanism_filter = plain, login
>
> did the trick. I didn't need to filter out XOAUTH2.
Whether through an explicit deny, or by omission, either way
the effect is to disable XOAUTH2. So the best hypothesis as
to the cause of the problem is that XOAUTH2 is supported and
preferred by Apple's SASL stack, but is not usable without
additional configuration and/or supporting application code.
So either Comcast added support for it recently, or your
machine was recently upgraded to support the new mechanism.
--
Viktor.
