[Mailman-Users] Ongoing delivery issues - First Yahoo, now AOL

Mark Sapiro mark at msapiro.net
Fri Mar 7 20:58:47 CET 2008

Rick Harris wrote:
>I posted a couple of weeks ago regarding mail not being delivered to Yahoo
>addresses.  I've all but written that off as an Internet black hole.
>Messages from my list almost never make it to Yahoo recipients.  If I post
>to the list, and cc a Yahoo address, then that works fine.  Background noise
>only, none of this matters today.

Since your original post on this issue, I have looked at my maillog and
I see lots of these

host e.mx.mail.yahoo.com[] refused to talk to me: 421 4.7.0
[TS01] Messages from temporarily deferred due to user
complaints -; see http://postmaster.yahoo.com/421-ts01.html

type messages (3500 in the last month, but only 46 in the last 5 days).
I also get lots of

host g.mx.mail.yahoo.com[] said: 451 Message temporarily
deferred - [250] (in reply to end of DATA command)


host c.mx.mail.yahoo.com[] said: 421 Message temporarily
deferred - 4.16.51. Please refer to
http://help.yahoo.com/help/us/mail/defer/defer-06.html (in reply to
end of DATA command)


host c.mx.mail.yahoo.com[] refused to talk to me: 421
Message temporarily deferred - Please refer to

The important thing is that in my case at least, every one of these is
successfully retried, either immediately via a different MX or after 1
or a few delayed retries. All of these messages were eventually
accepted by Yahoo and I have gotten zero complaints of missing mail
from Yahoo list members.

Perhaps there is some issue with your outbound MTA not retrying these
421 and 451 status returns.

>Today my question is about AOL.  Since I had the issues with Yahoo, I
>created my own email accounts on Yahoo, Gmail and AOL for testing and
>monitoring purposes.  This week, none of the list postings (4 or 5) arrived
>at either my Yahoo or AOL.  Yahoo is no surprise, but AOL was a surprise, as
>it has been perfect in the past.  As I said earlier, this list is small and
>has only one other AOL address, who also received no mail this week.  So, I
>went into test mode.  I turned off everyone on the list except my test
>account for AOL and sent another message to the list.  Came through just
>fine.  Personalization on or off makes no difference.  It works fine.  I'm
>very confused and open to ideas.

If you have only one AOL list member, it shouldn't matter how many
other non-AOL members are on the list. Your outbound MTA is going to
deliver a message to AOL with a single recipient in either case. AOL
shouldn't be able to tell the difference.

>  It shouldn't be so difficult to get
>routine messages through to a list of 25 people.

No, it shouldn't, but large ISPs have gotten so many complaints about
spam from their users that they are willing to sacrifice legitimate
mail in order to keep their users from complaining about spam.

I think there is a general problem here in that the typical large ISP
or free email service user is not a member of many or any lists. Also,
when these relatively clueless users receive spam, they complain to
the ISP/mail service, but when they don't get their list mail, they
complain to the list manager. So the ISPs/mail services think their
users don't want to receive spam and don't care if they don't receive
list mail, and they act accordingly.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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