Re: Missing messages [was: Stem forced to be at the right (or left) of the notehead]

[Brian Barker]

At 13:25 02/03/2018 -0700, Thomas Morley wrote:
> Paolo Prete wrote
> > ...
>
> For unknown reasons I don't see your posts on the mailing-list, ...

Neither do I. But I can help there: it's all down to Domain-based 
Message Authentication, Reporting and Conformance (DMARC). This is a 
comparatively new system whereby mail domains can publish information 
to confirm or otherwise that messages are genuinely sent from a mail 
server maintained by that domain. Paolo Prete's mail domain appears 
to be yahoo.it, and Yahoo is one of the sending domains that uses 
this system. If he sent to you directly, everything would work OK and 
Gmail would accept the message.

The problem arises with mailing lists. The server forwarding the 
message - in this case Lilypond's - is not a proper source for 
@yahoo.it messages, of course, so Gmail quite properly rejects list 
messages claiming to be from Yahoo addresses as spoofed. (As it 
happens, so does my mail provider.) If it is configured properly, 
mailing list software can arrange headers so that the receiving 
system - Gmail's in your case - sees his Yahoo server as the 
originator instead of the mailing list's. The problem is that most 
list software available when this protection was introduced was 
incapable of being properly configured. To avoid this effect, 
Lilypond may need to update the list software (apparently Mailman 
2.1.21) or maybe just configure it differently.

See
https://en.wikipedia.org/wiki/DMARC - which includes "In April 2014, 
Yahoo changed its DMARC policy to p=reject, thereby causing 
misbehavior in several mailing lists."
and
https://wiki.list.org/DEV/DMARC for details of Mailman's behaviour.

Brian Barker