Emails to Outlook.com rejected due to a fault or overzealous blocking rules

Bender 160 points 84 comments March 04, 2026
www.theregister.com · View on Hacker News

Discussion Highlights (20 comments)

TonyTrapp

I've had this exact problem for years. My IP addresses have been used for 15+ years for sending e-mail, they are spam-free, but Microsoft keeps blocking them. Every two months or so I have to ask them to unblock the IP again, then I can send mails to Outlook again, until they just random decide to block me again. It's an absolute clown show.

Alifatisk

I created my first Outlook account when I was young. Now, 30 years later and its still my primary account. I can't imagine how I would migrate to another email address if Microslop would begin ruining Outlook by forced subscription or something. My digital life is in M$ hands at the moment.

wccrawford

It feels like there's quite a lot of spin on this. There's no hint as to how many users were actually affected. It only really seems to mention Estonia, and probably only a region of it. The ISP there claims they haven't received any reports of SPAM. But that sounds wrong. No reports probably means your reporting system is broken. So putting that together, it seems like a small ISP screwed up and let spammers go wild, and Outlook blocked them for it. I can't really fault Outlook for that.

gzread

Everyone who runs an email server knows Microslop doesn't care about receiving its customer's emails. The best thing you can do is migrate away.

mono442

It's has been like this for a long time. For me hotmail is unusable because some emails just never arrive due to their spam filtering.

dismalpedigree

I’m guessing they connected CoPilot to the inbound filter and it is doing stupid and unexpected things.

mmsc

I wonder if Microsoft actually likes running their free email service still. They wiped a ton of old Hotmail and Live.com emails some years ago (and then allowed new people to register those deleted names). I imagine they don't get much out of it anymore.

arend321

I'm in the privileged position to advise clients to move away from hotmail/live if they want uninterrupted email delivery.

joshstrange

Just had a friend reach out yesterday about this issue. His outlook account for 10+ years started having issues receiving emails from his dad and a company he works with. All I could find was that his dad’s email was missing SPF/DMARC but the other email address that was having problems looked like it was configured correctly. I only was able to get a screenshot of the email voice his dad received and it mentioned being on a block list (like in the article).

boesboes

I've stopped diagnosing outlook/hotmail/live delivery issues about 12 years go, they simply do not give a single fuck about their customers. It used to be different, about 18 years ago orso, they had ways to contact them and resolve such issue. fuck big tech :)

Ensorceled

My clients have been experiencing this forever; the logs SAY "temporarily rate limited due to IP reputation." but really the emails are never going to get delivered. I have to get MailChimp or Mailgun to rotate the IPs. It looks like all it takes is one person to mark your email as spam, even by accident. Note that these are mailing lists which they signed up for in MailChimp case OR transactional emails in the Mailgun case. It's only hotmail/outlook that we constantly have this issue with, Google etc. are all fine.

Markoff

As long term Outlook.com user all I can say it's their service is extremely unreliable, my emails are either not delivered at all or end up in junk mail, some emails I don't receive at all or my partners are rate limited sometimes receiving their emails with hours long delays. I assume also their junk filters block some emails and there is no way to avoid it, you repeatedly add senders to safe senders list, even to safe subscriptions and their email still end up marked as junk even after years long communication from same addresses. As backup when something important I write email to recipient from gmail whether they received my email from outlook only to find out my email was never received.

gus_massa

A few years ago, in my university we have a big problem at the beginning of the semester to contact ~10K students, in particular when they register to our Moodle platform and the server sends them a message. Gmail was usually ok. Yahoo had some max messages per day. But Hotmail/Live/Outlook/whatever just made the messages disappear, no spam folder, no bounce, just disappear. We had some success telling the students to send us a message from their Hotmail/Live/Outlook/whatever address half an hour before registration. This adds our address to some special secret list for that account, and our later messages (usually) reach them. (It may fail. It may fail. IWOMM. YMMV.)

CrzyLngPwd

It's not just Outlook, it's all MS email products as well as Yahoo. These are emails that our customers have specifically requested and we get support tickets blaming us. It's been like this for years.

iamcalledrob

I was unable to reach a business this week who host their email on Office 365. Any email I sent would bounce with: 550 5.7.520 Message blocked because it contains content identified as spam. AS(4810)' For context, I was replying to an existing and very mundane email thread. Something is rotten in the state of Outlook

rbc

This is one of those articles that demonstrates why email should be distributed. Letting Google and Microsoft run email for the planet is just asking for problems. There are some technical demands to running email services, but they are still in reach of the technically inclined individual or organization. If for no other reason, it would help keep the big mail service providers honest.

cute_boi

microslop should start focusing on real world problem than overhyped ai bubble.

zelphirkalt

It is my experience, that Outlook is not a reliable e-mail service. Sometimes e-mails are not delivered, or only delivered hours later. When they are delivered, even as a paying customer, they are downloaded so slowly, that I had to wait 10 minutes to get all my e-mails, while my 1 EUR per month Posteo provider delivers in seconds. My impression is, that the only reason one would want to have MS as a mail provider is, that they are entrenched in the e-mail provider reputation and delivery game. Other than that, it seems to be an all around bad service. Not even talking about the mail client itself.

lousken

I was using outlook for communicating with businesses as it is often what they use. Some of them just could not send a response back to me, so I am not using outlook anymore. Just normal Microslop stuff

bradleyy

Having to explain to customers that they didn't receive an email because Outlook has a multi-stage set of email servers and the inside ones reject due to the edge (antispam) servers is always interesting.

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