We're having a weird problem with which our VPS hosting company (HostGator)
has not been helpful so far. After discovering that Yahoo was blocking our
outbound email, I discovered an anomaly in our exim_mainlog which appears
to be exim sending retries for a failed message with no delay in between.
About half of our mailing list has Yahoo hosted email, so these retries are
generating lots of attempts which is perhaps the reason we are still being
blocked.
Here's the (anonymized) log entry right after I sent a test message:
2024-09-26 01:56:20.185 [9856] 1stiQE-0002Yy-18 <=
bounces@??? H=(localhost) [XXX.XXX.XXX.XXX]:52212
I=[XXX.XXX.XXX.XXX]:587 P=esmtpsa L.-
X=TLS1.2:ECDHE-RSA-AES128-GCM-SHA256:128 CV=no SNI=cathouseonthekings.com A=
dovecot_login:via@??? S=58733 M8S=0 RT=0.009s id=
1727333780-1d2f9f6415ab0ec3e31fca8d5eecb841@??? T="Testing
- Please ignore" from <bounces@???> for
XXXXXXXXXX@???
2024-09-26 01:56:20.197 [9859] cwd=/var/spool/exim 3 args: /usr/sbin/exim
-Mc 1stiQE-0002Yy-18
2024-09-26 01:56:20.240 [9859] 1stiQE-0002Yy-18 Sender identification
U=cathouse D=cathouseonthekings.com S=via@???
2024-09-26 01:56:20.242 [9859] 1stiQE-0002Yy-18 SMTP connection outbound
1727333780 1stiQE-0002Yy-18 cathouseonthekings.com XXXXXXXXXX@???
2024-09-26 01:56:20.501 [9862] 1stiQE-0002Yy-18
H=mta6.am0.yahoodns.net [98.136.96.75]:25:
SMTP error from remote mail server after pipelined MAIL FROM:<
bounces@???> SIZE=60562: 421 4.7.0 [TSS04] Messages from
XXX.XXX.XXX.XXX temporarily deferred due to unexpected volume or user
complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
2024-09-26 01:56:21.015 [9862] 1stiQE-0002Yy-18
H=mta6.am0.yahoodns.net [67.195.204.73]:25:
SMTP error from remote mail server after pipelined MAIL FROM:<
bounces@???> SIZE=60562: 421 4.7.0 [TSS04] Messages from
XXX.XXX.XXX.XXX temporarily deferred due to unexpected volume or user
complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
2024-09-26 01:56:21.425 [9862] 1stiQE-0002Yy-18
H=mta6.am0.yahoodns.net [67.195.228.106]:25:
SMTP error from remote mail server after pipelined MAIL FROM:<
bounces@???> SIZE=60562: 421 4.7.0 [TSS04] Messages from
XXX.XXX.XXX.XXX temporarily deferred due to unexpected volume or user
complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
2024-09-26 01:56:21.926 [9862] 1stiQE-0002Yy-18
H=mta6.am0.yahoodns.net [67.195.204.72]:25:
SMTP error from remote mail server after pipelined MAIL FROM:<
bounces@???> SIZE=60562: 421 4.7.0 [TSS04] Messages from
XXX.XXX.XXX.XXX temporarily deferred due to unexpected volume or user
complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
2024-09-26 01:56:22.331 [9862] 1stiQE-0002Yy-18
H=mta6.am0.yahoodns.net [67.195.228.110]:25:
SMTP error from remote mail server after pipelined MAIL FROM:<
bounces@???> SIZE=60562: 421 4.7.0 [TSS04] Messages from
XXX.XXX.XXX.XXX temporarily deferred due to unexpected volume or user
complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
2024-09-26 01:56:22.334 [9859] 1stiQE-0002Yy-18 ==
XXXXXXXXXX@??? R=dkim_lookuphost
T=dkim_remote_smtp defer (-45) H=mta6.am0.yahoodns.net [67.195.228.110]:25
I=[XXX.XXX.XXX.XXX]:39744 DT=0.404s: SMTP error from remote mail server
after pipelined MAIL FROM:<bounces@???> SIZE=60562: 421
4.7.0 [TSS04] Messages from XXX.XXX.XXX.XXX temporarily deferred due to
unexpected volume or user complaints - 4.16.55.1; see
https://postmaster.yahooinc.com/error-codes
It looks like the server made a number of connection attempts within the
same second that the original message was queued. Multiply this by 10,000
or so Yahoo (@yahoo.com, @aol.com, @ymail.com, @verizon.net etc) addresses
and it looks like we are pounding on Yahoo.
This problem began last Friday and we have not made any changes to our
system configuration for exim or anything else in that timeframe.
Any idea what could be causing exim to retry multiple times in rapid
succession like this?
I've restarted the exim server but that hasn't fixed the problem. I've
removed all messages to our mailing list from the exim queue and now have
only one test message in the queue to monitor how it is being processed.
i'm not an exim expert, but am feeling the organizational pressure to get
this sorted :-(
Thanks in advance for any hints or suggestions.
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