Messages not delivered to Gmail over IPv6?

maddler

I’ve got two separate server from which I’m having issues while sending emails to Gmail, this only happens over IPv6.
Message gets accepted, I even get a delivery notification, but never lands to recipients’ mailbox.
This makes me think the actual issue is on Gmail but wonder if I’m the only one observing it and/or if anyone else managed to find a solution?
That’s pretty weird.

maddler

Email delivered but disappeared…

piperino

just tested from Sogo and K9 mail from my phone.
Both messages were deliverd via ipv6 to gmail and showed up in in gmail.
do have some sort of filter setup in gmail?

DocFraggle

Is your IPv6 reverse DNS correct?

Just tried it myself, works fine. Headers from Gmail:

...
ARC-Authentication-Results: i=1; mx.google.com;
       dkim=pass header.i=@domain.tld header.s=dkim header.b=Ropl+vz0;
       spf=pass (google.com: domain of user@domain.tld designates 2abc:458:c012:affe::1 as permitted sender) smtp.mailfrom=user@domain.tld;
       dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=domain.tld
Return-Path: <user@domain.tld>
Received: from mail.domain.tld (mail.domain.tld. [2abc:458:c012:affe::1])
        by mx.google.com with ESMTPS id n11-20020a05600c304b00b0041303fcf733si676059wmh.56.2024.03.07.00.48.41
        for <cool.user@gmail.com>
        (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
        Thu, 07 Mar 2024 00:48:41 -0800 (PST)
Received-SPF: pass (google.com: domain of user@domain.tld designates 2abc:458:c012:affe::1 as permitted sender) client-ip=2abc:458:c012:affe::1;
Authentication-Results: mx.google.com;
       dkim=pass header.i=@domain.tld header.s=dkim header.b=Ropl+vz0;
       spf=pass (google.com: domain of user@domain.tld designates 2abc:458:c012:affe::1 as permitted sender) smtp.mailfrom=user@domain.tld;
       dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=domain.tld
...

Maybe check your DNS settings, especially AAAA, SPF and reverse entry

maddler

Yeah, everything correct and everything working anywhere else. It just looks like Gmail is is black holing them for some (weird) reason and, as I said, I even get the delivery notification back from Gmail.
Anyway, I’ve tried again in the morning and looks like messages are now being delivered, for now at least.
Will see.

[unknown] no no filters or anything, message simply disappeared after reaching Gmail.
Anyhow, looks to be working now.
Will see.