Why am I unable to send an attachment with Outlook via SMTP that I am able to send via Gmail / Google Apps?

Question

I have Google Apps installed and I have tried to set up Outlook 2007 to send messages via SMTP.

I followed the guide, selecting what I believe are all the correct settings. Yes, I am using POP for incoming, that is intentional but I don't believe it should affect outgoing messages.

When I log into gmail (google apps) for my company, I can send a message that has an 8MB attachment (pdf file, not zipped or anything) and it sends fine. However, when I send the same message in Outlook with that same 8mb attachment it fails.

Why am I unable to send an attachment with Outlook via SMTP that I am able to send via Gmail / Google Apps?

The message headers are (some info omitted for privacy):

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the recipient
domain. We recommend contacting the other email provider for further
information about the cause of this error. The error that the other server
returned was: 552 552 #5.3.4 message size exceeds limit (state 17).

----- Original message -----

DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=company.com; s=google;
        h=from:to:cc:references:in-reply-to:subject:date:message-id
         :mime-version:content-type:x-mailer:thread-index:content-language;
        bh=7d4i/Cbt0v0sY3zt5lN6y5CdvxjbRmTBG4AuBuMxtF4=;
        b=IJwwxuIEdg1E4zXuGjeDod+1w3RYBBCNzSsqpuX77ih36HSiq++s3ZCQXPeU9CIZVg

K8JPJQu9xjivYYjrRaYwyeowLIu0GIdR2h4kKEkFM/GNC2RFF3VwVgj+gvi5eqVZIuWn
         osT5/VEm10IED6B54NPOtGMgFTci6a57zzVKE=
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=google.com; s=20120113;
        h=from:to:cc:references:in-reply-to:subject:date:message-id
         :mime-version:content-type:x-mailer:thread-index:content-language
         :x-gm-message-state;
        bh=7d4i/Cbt0v0sY3zt5lN6y5CdvxjbRmTBG4AuBuMxtF4=;
        b=LjTecjok5K71Bymp6tZqAL2XCz03hWROV1mTK8Vf2AeEJwtel9ACu9kE5jW5iJqckb

upYKPzoqYLBwAPOzMb9asWoTAZPzC7LMG65eDUc2/ZEvGqXrZs3ziUxwhF4t169yRVuy

/6nm/aAt5uPMLPdobxGTJ8ahOIku1Z3gW+OcvZ6ERk1Av/bvuln09vcnyJIrHGh7eK8n

cbGVxmK0aecgSPgIj2NALbHkyuxwj+LEBRV6uiz3THDjxAiNfsO5UFjV59sD+lVSBT3z

ThOGE8WEXRnKHuP3FuKXyeUxKBZ2CxpWJpvDuS9EsFkln7zkISYEsRA0nUA6GSGi2Z/n
         8YUg==
Received: by 10.60.169.197 with SMTP id ag5mr12254920oec.137.1351036287413;
        Tue, 23 Oct 2012 16:51:27 -0700 (PDT)
References:
Date: Tue, 23 Oct 2012 19:51:16 -0400
Message-ID: <003a01cdb179$4bb2ca60$e3185f20$@com>
MIME-Version: 1.0
Content-Type: multipart/related;
        boundary="----=_NextPart_000_003B_01CDB157.C4A12A60"
X-Mailer: Microsoft Office Outlook 12.0
Thread-Index:
Ac2xVCHGxoC7DDOkQBK3JSXowHb0EQAEB7agAAA/YKAAAIGcQAAAngfQAABAAPAAAFe7gAAAadvw
AALgvLA=
Content-Language: en-us
X-Gm-Message-State:
ALoCoQniMq7Fnh+NlfoWjTJPvKWbkhEaftSaFo9ZVvtRpWufTmhlRDx1a9Jf+wmYcbRh896gygNr

The company I am sending email to is a company that uses Google Apps for Teams. This is their apps admin login. Should I be worried about that message?

My Settings

On the Google apps side I have set my SPF record and set / verified my DKIM key. Here are my outlook settings:

Why am I unable to send an attachment with Outlook via SMTP that I am able to send via Gmail / Google Apps?

update Per request via comments, here is the setting for outbound relay in Google Apps:

Solution

My best guess would be that Outlook is using the Quoted-Printable encoding for your attachment, which would make it much larger than the original.

You may want to try and follow the directions in KB 278134 and edit the InternetMailTextEncoding key in the HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Options\Mail registry subtree. If you assign a DWORD value of 2 (use Base64) or 3 (don't encode, send 8-bit attachments) to it, and that solves the problem, then you'd have found the culprit.

Comments

[laika]

Just to clarify: you're sending the message with the same 8 mb content to the same recipient, once via Outlook configured to use Google Apps, and the second time via Gmail frontend of Google Apps. Am I right?

[cwd]

@skrco - yes that's right. that's why it's perplexing.

[laika]

One more question then... What is the value of this checkbox Google Apps Cpanel -> Settings -> Email -> Outbound relay -> Allow users to send mail through an external SMTP when configuring a "from" address hosted outside your email domains?

[laika]

btw whois is saying that they no longer use google apps for email delivery

[cwd]

@skrco - that is the receiving domain. also updated the question with a screenshot - it was checked already. thanks for working hard on this one.

[laika]

Sounds interesting. You were trying to post the 8 MB email using the two methods at the same time? Or there were delay between those two messages?

[cwd]

@skrco - i tried one. then the other. then the first. tried a few times over a span of a few hours.

[cwd]

it's not an exchange server. It is just Outlook sending via google apps' smtp

[PJC]

This could well be the culprit - the key indicator is that it's the recipient domain that's rejecting the message, not Google itself. So the issue isn't that you can't send it, but that it is being rejected by the recipient.

[cwd]

seems to have fixed it (fingers crossed)