Emails to Outlook always flagged as SPAM

Hi all,

I’ve playing for a few days with MIAB and I’ve just noticed that all my emails to Outlook are flagged as SPAM.

here is the header of the email I sent to my Outlook address:

Authentication-Results:; spf=pass (sender IP is XX.XX.XX.XX; identity alignment result is pass and alignment mode is relaxed); dkim=pass (identity alignment result is pass and alignment mode is relaxed); x-hmca=pass
X-SID-Result: PASS
X-Message-Status: n:n

I did a check on and I got a score of 10/10, also my ip is not blacklisted.

No problem with Gmail…

Anyone has this issue ?


Could this happen if someone else on Outlook marked a message from you as spam? Maybe try marking them as “not spam” to help retrain Outlooks spam filters?

Well it seems that this issue does not only affect MIAB. I’ve tried with different email providers like protonmail or openmailbox and their emails always end up flagged as SPAM…

So either it’s my few Outlook account that are over spam-protected or it’s Microsoft playing with people hosting their emails…

Yes. And unfortunately there’s not much you can do in a situation like this. Hopefully marking the messages as “not spam” will help some, but it might be a long shot.

Why pay for Microsoft office anyway? OpenOffice, thunderbird, etc are all free and run great on windows!

I was under the impression that we’re talking about accounts and not the mail client.

I didn’t even think of that, good call!

Anyway, is that even possible? setup to get your email from MIAB?

I assumed OP meant that when they send emails from their MIAB address to an address it keeps getting marked as spam. They said that they’re experiencing this when sending email using other providers such as protonmail and openmailbox as well.

This really seems like an spam filtering problem. This is why I recommended simply marking the messages in the account as “not spam” which will hopefully help train the spam filter. But as I said, that may be a long shot.

One thing to try is to make sure his External DNS is setup according to his MIAB external DNS config, this will help prevent him from being marked as spam. ( will check SPF, TXT, and SRV records to confirm emails are coming from their proper source.) Multiple MX records that show and say are also not recommended (Multiple MX records for pointing to different servers will flag you as spam as well.)

cdllm: I don’t think marking the message as non-SPAM will fix the problem, it may fix it for my Outlook address but surely not for others (otherwise it would be very easy to go around Microsoft filtering) and that’s my point, I don’t want Outlook to flag my mails as SPAM for all its users…

murgero: My configuration is clean and is the one automatically generated by MIAB, I’m not using any external DNS server.

Has anyone of you tried to send emails from his/her MIAB to an Outlook address without being flagged as SPAM ?

I cannot confirm this as I do not have an account, but I will signup for one and take a look.

I will post with results in a little bit.

I was flagged as spam,

Here is why: SPF and DKIM both fail and as a result, DMARC fails, once DMARC fails, the email is instantly flagged as spam. (DMARC can still fail even if SPF and DKIM are OK)
Example Fail message:

    Received: from authenticated-user (unknown [])
	(using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits))
	(No client certificate requested)
	by (Postfix) with ESMTPSA id 0E3473E0EB3
	for <>; Fri,  3 Apr 2015 11:42:08 -0400 (EDT)
Authentication-Results: box; dmarc=fail

You can find out the cause of the fail by right clicking the email in and selecting View Message Source. (You may have to move it to the inbox first.)

Thank you murgero for your results.

So in your case it’s clear there is something wrong about DKIM and SPF records, but in my case, it says everything seems ok, both DKIM and SPF passed, so there should be no reason for my mail to end up in SPAMS…

Does DMARC still fail though? because all 3 need to pass to get marked as normal mail as far as is concerned.

Have you tried sending to a gmail account? Just to confirm your box is not blacklisted somewhere?

There is no fail result anywhere in the headers, and no mention of DMARC as well, and as said in the first post, gmail does not flag my mail as SPAM.

My IP and the domain I use are clean, I use them mainly for testing

You don’t have anything that matches this? ^^

If you’d like I can send you an email from my MIAB address to your address to verify that it’s not just your MIAB installation.

yeah -

I’ll take a look at the headers and see if you might have missed something.

Ok I sent an email from the domain.

I will check that shortly, user this tool: to validate your SPF and DKIM just to confirm.