Tuesday Tip: Gmail doesn’t discard!


Time for another Tuesday Tip here on Spam Resource.
Tuesday Tips are meant to be short little bits of wisdom, easily digestible deliverability knowledge nuggets.

Today's topic for the Tuesday tip tis this: Gmail does not discard email messages.

You might be thinking right now: But that's not true! I'm having trouble delivering emails! And my emails to Gmail are disappearing, I can prove it!

And it's true. Every once in a while somebody reaches out to me with this issue, exactly as described.

But then we dive deeper into the issue. And we invariably find that they were wrong. That in this case, sending an email message to a Gmail mailbox does not result (and should never result) in that email message being discarded. If you think that's happening, there are a few things that could actually be happening instead, and it pretty much HAS to be one of these two things. It could be:
  1. Mail is being delayed significantly. The mail in question is stuck in the outbound MTA (mail server) queue and every time delivery is attempted, Gmail is responding with a 4xx error.
  2. Mail is being rejected. You just don't see that, because you're not checking the outbound mail server logs, or the return-path address is going some place you're not checking or monitoring. Your sending domain needs to be valid and able to accept and/or deliver mail, and the sending address for the return-path of your email messages must be valid and you need to be able to receive messages sent to it.
Why is this happening? There are numerous possible reasons.
And in some of those cases, Gmail will absolutely leave this mail in limbo -- stuck on your mail server, rebuffed (deferred) with a 4xx error repeatedly. Sometimes limbo lasts for only a few hours; but sometimes, it effectively lasts forever. In that instance, nothing changes until your outbound mail server or send platform gives up and stops trying to send.

That's sometimes why you suddenly get a burst of reported bounces back in certain ESP and email automation platforms some period of time -- often 72 hours -- after you hit send. In that case, the mail was being deferred with a 4xx response by Gmail for the whole time, and the send platform only now just gave up and logged bounces. 

It could even be that you have a testing process that sends mail to a specific Gmail address too often (or to a public address that's being used by too many people for testing at the same time). Or that you're sending to an email address associated with an account that has been deleted because nobody has logged into it for a couple of years.

You won't know until you find the error message. Check your outbound mail server's mail logs. If you use an ESP or email marketing automation platform, ask them if they log SMTP transaction information so that you can review it and see for yourself. And remember that some platforms just don't make this information available -- which leaves you significantly blind to mail delivery troubleshooting.

If you're sure that you've sent the message, and you're sending it to your own test Gmail account, and you're sure that it hasn't arrived yet, or you can't find it anywhere, then the only things left are to check the recipient's spam folder, AND to make sure that the Gmail account in question doesn't have an email filter rule set up to delete or otherwise hide messages from that sender. Yep, that has happened!

And yep, I've seen all of these things happen! Some of them more commonly than others. But what I haven't seen any real evidence of, in many years, is mail actually being accepted by Gmail and then silently thrown away.

TL;DR? Check your mail server logs, make sure the sender (return-path address is routable and readable), and make sure it's not something silly like an email filter rule run amok.

And when you're done enjoying today's Tuesday Tip, why not head over to the Tuesday Tip archive here on Spam Resource to look for more delicious info-nuggets?
2 Comments

Comments

  1. With respect, that is not correct. I'll accept that it is rare that Gmail discards, and their automated spamfiltering systems probably don't, but there are cases where Gmail does discard.

    I was moving a mail server for a small hosting company to a new IP range, with the old IP still available and sending mail. Correct rDNS/SPF/DKIM, consistent EHLOs matching publicly facing hostnames, trusted certificates matching the public-facing hostnames, pretty much as simple/textbook example as it gets. No meaningful DNSBLs (APEWS or something). Did a gradual warm-up, although the system was low-volume enough that it was probably below the normal "warm-up" thresholds anyway. Person-to-person and possibly a bit of genuine transactional. We measured in units of months-between-abuse-reports, not abuse-reports-per-month. Webserver generated messages including contact forms used another SMTP server with separate DKIM.

    It was mostly good everywhere. Yahoo accepted like 3 messages an hour or something silly like that, but anything that failed would just go through the old server, so whatever, just took it slowly.

    But Gmail? SMTP accepted, and that was that, nothing in the Inbox, nothing in the Spam folder, just... *poof*. Ended up reaching out on an antispam mailing list and went around in circles a bit because "Google doesn't discard", then someone from Google reached out and indicated that there was a rule discarding the mail, fixed it up, and that was that.

    From what I recall of the conversation he did say that it was unusual, and that a human postmaster had created the rule. Maybe things have changed, but at least in the past Google did discard mail in rare cases.

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  2. Hey, I always welcome data that suggests I reconsider my position. This doesn't do it for me, though; only getting 3 msgs/hour to Yahoo and Gmail had a "special rule" discarding your mail... something else was up here. There's more to this one. Nor does it offset the many other times I've tried to have people tell me that they're sure that Gmail is discarding their messages when that's not what is happening.

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