Outlook.com email problems are hitting UK inboxes, with Microsoft’s free consumer mail service bouncing some perfectly legitimate messages since Thursday 5 November. Senders are being told their email “lacks SPF/DKIM/DMARC Auth Records”, and it is catching small businesses and personal domains as well as bulk mailers. If you use an Outlook.com, Hotmail, Live or MSN address, you may be missing messages without knowing it.
What is going wrong with Outlook.com and Hotmail email?
Reports began to build late last week on Microsoft’s own forums, on Reddit and on the Mailop mailing list used by email administrators. The most common bounce reads 550 5.7.1 Message rejected: Message lacks SPF/DKIM/DMARC Auth Records (AS9031519). Some senders instead see 550 5.7.23, which points to a Sender Policy Framework (SPF) failure.
Windows Latest says emails have been rejected since at least 5 November, and that it reproduced the fault on 8 November after a business could not reach its writer. Neowin has also reported the problem, noting that several businesses are affected, which suggests it is not an isolated configuration mistake.
Why valid senders are being blocked
The pattern is not tidy. Some senders say their SPF, DKIM and DMARC records are all in order and their mail still bounces. One forum user said the failures hit only a small percentage of messages, and Windows Latest notes that some emails go through on a second attempt. That fits with reports that the rejections may depend on which Microsoft server handles the message.
Email deliverability specialist Al Iverson of Spam Resource tested the behaviour on 7 November. He removed the DMARC record from several low-volume domains and sent mail to an Outlook.com address, which was rejected. The same mail sent to a Microsoft 365 business address was accepted. That points to the change affecting consumer services (outlook.com, hotmail.com, live.com and msn.com) rather than Microsoft 365 tenants.
Has Microsoft confirmed a change?
Not as far as we can find. At the time of writing there is no public statement explaining the rejections, no fix and no announced policy shift. Microsoft does have a published rule for high-volume senders, introduced in 2025. It covers domains sending more than 5,000 emails a day to its consumer services, and those rejections use a different code, 550 5.7.515. The current bounces are reaching far smaller senders, so they do not appear to be that rule at work.
It is therefore unclear whether this is a deliberate tightening, an early rollout of stricter checks or a fault. Treat any explanation as unconfirmed until Microsoft says otherwise.
How to fix it if you send email from your own domain
Several administrators report that the quickest remedy is to publish a DMARC record, even a relaxed one. Many affected domains had working SPF and DKIM but no DMARC record at all. Microsoft 365 does not create one automatically for custom domains, so it is easy to miss.
- Log in to wherever your domain’s DNS is managed, which is often your registrar or web host.
- Add a TXT record with the name _dmarc (some hosts want the full _dmarc.yourdomain.co.uk).
- Set the value to v=DMARC1; p=none. The “none” policy asks receivers to take no action on failures, so it should not change how other providers treat your mail.
- Check that SPF or DKIM passes and aligns with the domain in your visible From address.
- Wait for DNS to update, then resend any bounced messages.
If you do not run your own email system, send the full bounce message to whoever hosts your mail, your website developer or your marketing platform and ask them to check the domain’s DMARC record.
What Outlook.com and Hotmail users should do
Recipients cannot fix this themselves, because the rejection happens before a message reaches the inbox and nothing lands in Junk. If a supplier, school, GP surgery or online shop says it emailed you and you saw nothing, ask them whether they received a bounce. Where possible, give important contacts a second address, and check the sender’s domain if you manage one yourself.
This is a good moment for UK small businesses and clubs to check their own domains. Anyone sending from a custom address to customers on Hotmail or Outlook.com should confirm that SPF, DKIM and DMARC are all published. Free online DMARC checkers will show whether a record exists.
What happens next
The wider direction of travel is towards stricter sender authentication, with major mailbox providers asking for DMARC as standard. Whether Microsoft rolls this change back, formally announces it or leaves it in place remains to be seen. For now, publishing a basic DMARC record is a low-risk step that takes a few minutes. We will update this story if Microsoft comments. Full details of the original reports are on Windows Latest.
One of the Editors for Tech on the Go, I love covering mobile tech and social media. I also manage the reviews we cover so all the writers stay on my good side!
