What does error "S3150" mean?

Question

Hello,

This week I reported over a thousand phishing spam to "@outlook.com" and to "@office365.microsoft.com" that were sent from Outlook. There was the usual Outlook spam in there too, offering to improve my SEO or build my web site, but a vast majority of the spam were from the same PHISHING campaign that Microsoft has allowed to run for months.

Apparently because I sent so much abuse to a Microsoft address, and apparently because Microsoft lacks both common sense and self awareness, my email server's IP has added to a blocklist.

However, Microsoft isn't clear about what, why, how, or what to do about it:

550 5.7.1 Unfortunately, messages from [173.198.243.126] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [VE1EUR01FT080.eop-EUR01.prod.protection.outlook.com 2024-02-02T21:37:21.315Z 08DC2164772DB05A]

Ok. So we're on Microsoft's blocklist. So I visit that link above, and guess what? It has nothing about the only error message indicated ("S3150"). It has nothing about blocklists.

So how do I:

1. get off this blocklist?
2. get someone at Microsoft to realize how insanely ridiculous it is to put someone on a blocklist for sending abuse complaints to abuse addresses?
3. get someone at Microsoft to DO SOMETHING ABOUT THOUSANDS OF PHISHING SPAM CONSTANTLY COMING FROM OUTLOOK?

Thank you,

John Klos

Answer 1

Is Microsoft SERIOUSLY blocking my IP address?!

My customers can't get my emails, and I'm left in the dark! They pull this stunt of blocking my IP address with NO WARNING and NO WAY to unblock it? This is UNACCEPTABLE! My business is suffering because of Microsoft's ridiculous decision.

Answer 2

Dear Vince R.

There is a totally misleading point in your answer!!

==> "This can happen if Microsoft detects spam or other malicious activity coming from your IP address. "

I am astonished how often I find this problem reported and how often NOBODY can answer properly.

( BTW: I have also  been suffering from this problem for years. MS does not provide a helpful solution - really annoying. )

a) "S3150" error is NOT a problem of (your) Hotmail.com/Outlook.com/Live.com mailboxes.

b) "S3150" error is NOT a problem of YOUR IP address.

MS is blocking the entire IP range of your ISP/service provider. Someone ELSE from your ISP is spamming the Internet from that range and you (and the whole ASN IP range) are suffering. MS wants customers to put enough pressure on those ISPs/service providers to find and stop their customers who are flooding the Internet with spam emails.

A very similar approach is a spam blacklist service from uceprotect.net – they call it “UCEPROTECT-Level3” – see FAQ http://www.uceprotect.net/en/index.php?m=3&s=5. So, you can get an idea, how such mechanism works ( uceprotect is NOT related to the MS S3150 blocklist, but probably a very similar approach)

So, the only thing you can do (about every 2-3 month…) to report your IP  to the URL (which is a ticketing system) you  have given and ask for removal/mitigation. I have done that already more than 20 times ...

Thanks

Martin

Answer 3

• May I know how do you access your emails? is it through Outlook.com (web)? Outlook application (included in Microsoft 365 subscription)? New Outlook for Windows? Classic Outlook for Windows (Windows Mail app)? Outlook application for mobiles?

How is this relevant? The issue is that I have trouble sending email to Outlook.com because Outlook.com put me on a blocklist because I reported abuse.

But if you must know, I use alpine.

• I would like to know what @domain and who is hosting your email account? example for @domains: Gmail.com, Yahoo.com, Outlook.com/Hotmail.com

The domain I use is @klos.com. I am hosting it on my own servers.

• May I know if the account is for Work/School use? or Personal (Hotmail/Outlook.com) use?

May I ask what kind of toilet paper you use? It's about as relevant as whether I use my own email account for work, school or personal use.

• Can you still sign in with your account in https://outlook.live.com/ ?

I'm signed in now so that I can correspond here. That's not the problem, and you'd know that if you read what I wrote instead of sending form responses.

• Is this happening to all other devices, browsers, and network?

Is my email rejected by Outlook.com when I use a different device, browser, or network? I don't think you understand how SMTP works if you think my choice of browser or device affects deliverability of email between a real, proper SMTP server on the Internet and Outlook.com.

It seems that my IP has been de-listed, finally. However, it's not clear if I'm going to be listed again because I choose to report spam from Outlook.com to Outlook.com. Why does it take extraordinary energy to communicate with anyone who has a clue at Microsoft?

But what really matters is why is Outlook.com allowing the same, exact group of scammers to send countless phishing spam over and over and over and over, and Outlook.com does absolutely nothing about it? In the past you let these scammers claim they were MAILER-DAEMON; now you let them use any date they want, such as Sat, 3 Feb 2216.

It's ridiculous, and it's completely irresponsible for Outlook.com to facilitate these scammers and facilitate literal harassment.

John Klos

Answer 4

I am also facing this issue, both on old and new servers/domains that I setup.

The error is the same even with a new IP addresses and based on what I read in the troubleshooting page:

Are you sending email from new IPs?

IPs not previously used to send email typically don't have any reputation built up in our systems. As a result, emails from new IPs are more likely to experience deliverability issues. Once the IP has built a reputation for not sending spam, Outlook.com will typically allow for a better email delivery experience.

New IPs that are added for domains that are authenticated under existing SPF records typically experience the added benefit of inheriting some of the domain's sending reputation. If the domain has a good sending reputation new IPs may experience a faster ramp up time. A new IP can expect to be fully ramped within a couple of weeks or sooner depending on volume, list accuracy and as long as their junk email complaint rates are kept at a minimum.

If you ask me that makes no sense.. I buy a new domain name and set up a new server with a new static IP for a client and they just block its mail system right away.. What am I suppose to tell my clients? To just wait and see if microsoft will trust our IP in a couple of years?

Which is also not likely to happen.. I own some servers for years and their IP is still is blocked, even though no spam is sent from domains hosted there. And of course, it's not possible for the client to wait, because they need to run their business through their website, eshop, service etc.

This is one of the oldest issues for microsoft associated email accounts, and I don't see it getting fixed for decades now.

So, the only "solution" I can see is to just mention on websites that microsoft email accounts are not accepted, for reliability issues, as they are the only ones that by default have trouble accepting emails. Use anything else and your problem is solved.

Answer 5

You are absolutely on point here. Today I found my ip blocked by outlook servers without any reason I could see. Not a single mail to msn/hotmail/outlook/whatnot during last week or before today and there it is, S3150 error.

Thanks a lot Microsoft.