Gmail thinks “This message may not have been sent by…” you

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13 Responses

  1. Brian says:

    Ok, so what’s the simplest way to fix this?

    In my case, I send out messages to a maling list via The reply-to address is Gmail. I see the error for a Gmail recipient. So what do I do?

    • Jon says:

      I never heard any confirmation of what the exact cause is, but the two likeliest options A) are failed DKIM or B) domain name not matching server names.

      Either way, I suspect the fact that the mailing list address not being at (which is the server actually sending out the messages) is the problem. Your best bet is to use an address from them instead. Or tell them about the problem and see if they can fix it.

      I haven’t seen the problem pop up much recently from mailman based lists, so I presume they implemented a fix of some sort.

  2. George B. says:

    I have a web front end that sends out group emails using the senders email address, whatever that may be. Was getting this same warning. But after I set up a valid SPF entry for the hostdomain I send from, the warning no longer appears, instead the “from” appears like ”sender-name via”. Note that in the sendmail command I specify the returns (bounces) to come back the an email address on the hostdomain, not sure if that made a difference or not.

  3. David says:

    The only emails I saw these warnings on are on those sent by Youtube Lol… I checked the senders address and the msg originates from the actual Youtube domain.. way to go Google!!

  4. Matthew says:

    Ok, after actually doing some research, I think I understand this. The warning appears on messages from Gmail users because Gmail adds a DKIM signature on outgoing messages, and now expects a valid DKIM signature when it receives a message claiming to be from a Gmail account. DKIM signatures are often invalidated by mailing lists, due to message footers or subject-line prefixes added by the mailing list software.

    I don’t see this warning on messages from non-Gmail users, probably because those messages come via providers that don’t do DKIM signing, or perhaps because Gmail isn’t (yet) as strict with messages claiming to be from non-Gmail domains.

    DKIM is a good thing, I think, so this is probably the right direction to be heading. But the breakage with respect to common mailing-list practice should have been foreseen. I think the “Learn more” link in the warning should at least explain this particular case, and perhaps there should be an option to disable the warning for specific mailing lists.

    • Jon says:

      Good catch. That is indeed the case. We’ve got a private mailing list (through a mailman) and while we use Google Apps, we don’t DKIM. The only messages I’ve see this warning on are, as you pointed out, Gmail users.

    • Ali S says:

      Thanks for researching this – the funny (sad) thing is that even google groups behaves this way, stripping out the DKIM!?! I routinely receive messages to my gmail account, sent from other gmail users via mailing list, which display the “message may have not been sent by” alert … yet the mailing list is a google groups-hosted group!!

      Doctor G, heal thyself.

    • Jaime says:

      Thanks Matthew for your research. It happens too sending mails from the Gmail Android app!!, so every mail I send from my phone everybody see that message!!

  5. Matthew says:

    How’s this for irony: I get this warning on almost every message sent from a Gmail account to a mailing list I’m subscribed to, and haven’t seen it on any message sent by a non-Gmail user.

  6. John says:

    How odd, I have yet to see this message.

  7. Ela says:

    I’m on a lot of email lists, too, and I’ve gotten this message a lot. So far, every single message (including my own messages that have been so labeled!) are legitimate messages. So I’m getting pretty darn annoyed by this so-called improvement.

    • whyisitso says:

      Like you Ela, i find Google’s interference with my communications extremely irritating. Gmail is generally an excellent emailing system, with a lot more going for it than hotmail or yahoo, but this nannyism is getting past a joke. I do wish they’d ease up.

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