I've gotten bitten by this too, as I had my homebrew mailing list manager intermittently generating messages with two message ID headers -- but not in the past few days -- more like a couple of months ago. So it could be new-ish, I guess.
Cheers, Al On Wed, Jul 13, 2022 at 5:34 AM Philip Paeps via mailop <mailop@mailop.org> wrote: > > On 2022-07-13 17:52:33 (+0800), Laura Atkins wrote: > > On 13 Jul 2022, at 09:07, Philip Paeps via mailop <mailop@mailop.org> > > wrote: > >> On 2022-07-13 15:31:17 (+0800), Philip Paeps via mailop wrote: > >>> In the past couple of days, I'm seeing an uptick in rejects from > >>> Gmail as follows: [...] > >>> > >>> As far as I can tell, the message is compliant. It doesn't have any > >>> of the obvious problems, at least. From, To, Message-ID and Date > >>> are supplied. No duplicate headers. > >> > >> It turns out there was, in fact, a duplicate Date: header. Sigh. I > >> am blind. I was looking for duplicate To: headers, which are a lot > >> easier to introduce. I wonder how that happened. > >> > >> Apologies for the noise. > >> > >> (Still wondering if Google has gotten stricter though... As far as I > >> know, this commit mail script hasn't been touched in a very long > >> time. Though I won't exclude the possibility of something else in > >> the mail pipeline having changed.) > > > > There are currently quite a number of anecdotal reports that Google is > > moving towards rejecting more email that doesn’t comply with their > > interpretation of the standards. This includes 5321/2 and the > > authentication standards. > > For fans of anecdata... :-) > > The duplicate Date: header was introduced on 2021-06-05 at 11:00:56 UTC. > > As far as I can tell, we saw our first reject on 2022-07-08 at 23:15:18 > UTC. > > We only keep 7 days of outbound logs and this this particular script > only sends a handful to a few dozen messages daily. A slow enough > trickle for patterns to take a while before becoming obvious. > > Philip > > -- > Philip Paeps > Senior Reality Engineer > Alternative Enterprises > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop -- Al Iverson / Deliverability blogging at www.spamresource.com Subscribe to the weekly newsletter at wombatmail.com/sr.cgi DNS Tools at xnnd.com / (312) 725-0130 / Chicago (Central Time) _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
