Emails to outlook being dropped

sirpumpkin · October 22, 2017

On 19.3.2016 at 5:03 PM, colonel_mortis said:

In theory, emails to microsoft domains should now be working. If it's not, please let me know and I'll see what else I can do.

Hey there,

sorry for bumping this thread, but I'm really hoping to find a solution here. I have a similiar problem - mails from my own mail server are accepted by Microsoft and then just silently deleted. This is obviously a big problem for me. I've never sent any spam mails or unwanted mails.

What did you do to fix the problem? Maybe it could help me.

Thank you for your help

colonel_mortis · October 22, 2017

10 minutes ago, sirpumpkin said:

Hey there,

sorry for bumping this thread, but I'm really hoping to find a solution here. I have a similiar problem - mails from my own mail server are accepted by Microsoft and then just silently deleted. This is obviously a big problem for me. I've never sent any spam mails or unwanted mails.

What did you do to fix the problem? Maybe it could help me.

Thank you for your help

I believe the solution in this case was that we switched to a different provider, because there was nothing that we were able to do on the existing provider that helped. However, in general I would recommend ensuring that you have an SPF record set up (to whitelist permitted IP addresses) and ideally DKIM signing though that can be slightly more involved. Also make sure that your IP/domain isn't blacklisted (https://mxtoolbox.com/blacklists.aspx) and that your server has the appropriate authentication so spammers can't send emails through it either with their own or your address.

-split into a separate topic-

Edited October 22, 2017 by colonel_mortis

sirpumpkin · October 22, 2017

Hey,

thanks for your quick reply.

Yeah, it is a very unfortunate situation. I used another server a few months ago and had no problems but had to switch the server as well the IP for unrelated reasons. On Friday I got a NDR when sending mail to Outlook:

host mx3.hotmail.com[104.44.194.234] said: 550 SC-001
    (SNT004-MC8F21) Unfortunately, messages from xxx.xxx.xxx.xxx weren't sent.
    Please contact your Internet service provider since part of their network
    is on our block list. You can also refer your provider to
    http://mail.live.com/mail/troubleshooting.aspx#errors. (in reply to MAIL
    FROM command)

I then contacted Microsoft using this form. Just 30 minutes later they told me that my IP was "conditionally mitigated" and that it should be now possible to send mails. After 48 hours, the bounces stopped, but now the mails are just silently dropped. I'd prefer them being rejected actually, lol. Now me and my users have no way of knowing whether the mails arrived. It is unbelievable. I have no problems with any other regular mail provider.

I have configured SPF and DKIM, I'm blacklisted nowhere, my IP reputation is good, I'm not running an open relay, I rarely send mails at all, I signed up for Microsoft SNDS... https://www.mail-tester.com/ says my score is 10/10.

I replied to their eMail in the hope of more help but due to my experiences at work and after reading about it online, I guess I will just get the same copy-pasted responses all the time and there will be no real way for me to solve this. It seems that I have to build up reputation with my IP, well, big senders may be able to do this and "warm up" the IPs, but I personally can't afford lost outgoing mails, since it is just private mail / related to a club I'm providing the mail server for. We are just sending a few mails per months, we aren't a big sender at all.

I'll probably use a SMTP relay like Mailgun / Mailjet / Sendgrid for outgoing mails, but I don't really like this solution. It also brings some privacy issues with it (I'm from EU, so...). Oh well