How do you get email delivered to Outlook.com and Hotmail?

Outlook.com, Hotmail, Live and MSN addresses all run on Microsoft's consumer mail service, and it has its own filters, tools and support channel. They are separate from Microsoft 365 business tenants. If your newsletters, receipts or alerts land in Junk or bounce there, this guide covers the tools Microsoft gives senders, its 2025 authentication rules and the bounce codes you're likely to see, as they stand at the time of writing (October 2026).

Why does Outlook.com handle mail differently?

Outlook.com is a consumer mailbox provider. Its Postmaster site says its filters "are influenced by a number of factors related to the sending IP, domain, authentication, list accuracy, complaint rates, content and more", and that "one of the principal factors in driving down a sender's reputation and deliverability is their junk email complaint rate."

A Microsoft 365 business tenant is different. Its filtering is set by that organization's admins, who can allow or block you independently. If your mail is junked by a company using Microsoft 365, our guide to Microsoft 365 emails going to Junk is the better starting point.

What does Outlook.com require from senders?

Requirements for everyone

Outlook.com's Policies page lists technical rules for every sender, including:

• Comply with IETF standards for internet email.
• After a permanent error (a 5xx code), don't retry that message to that recipient. After multiple 5xx errors, stop mailing that address.
• Don't open more than 500 simultaneous connections without arrangement.
• Make unsubscribing "clearly documented and easy for recipients to find and use."
• Connections from dynamic IP space "may not be accepted."
• Mail servers "must have valid reverse DNS records."
• Don't use namespace mining, which means checking whether addresses exist without sending to them.

Check your sending IP's reverse DNS with the PTR Lookup. Our guide to reverse DNS for mail servers explains the fix if it's missing or generic.

The 2025 high-volume sender rules

On April 2, 2025, Microsoft announced requirements for domains sending more than 5,000 emails a day to Outlook.com:

It also recommends a valid From or Reply-To address that can receive replies, a working unsubscribe link, list hygiene and bounce management, and transparent practices such as accurate subjects and consent.

The original plan was to send non-compliant mail to Junk first. An update on April 29, 2025 changed that. Microsoft said it would reject non-compliant messages with 550; 5.7.515 Access denied, sending domain [SendingDomain] does not meet the required authentication level, starting May 5, 2025. Outlook.com's own Policies page still describes non-compliant mail going to Junk first, with rejection "if issues remain unresolved", so plan for either outcome. Our bulk sender requirements guide compares these rules with Gmail's and Yahoo's, and the 550 5.7.515 reference covers the fix.

Check your records with the DMARC Checker, and send a real test with the Deliverability Test to confirm SPF, DKIM and DMARC actually pass on your mail.

What is SNDS and how do you set it up?

Smart Network Data Services (SNDS) gives you Outlook.com's view of IP addresses you own. Microsoft describes it as "a free service that provides high-level insight on how users are rating the email they receive and the health of your IP space" (Outlook.com Postmaster).

Can you use it?

Only for IPs you can prove you control. SNDS authorizes access using reverse DNS, RDAP registration records and the internet routing table (SNDS FAQ). If you send through Microsoft 365, Google Workspace or an email service provider on shared IPs, those IPs aren't yours to register. Ask your provider instead.

Signing up

1. Sign in to SNDS with a Microsoft account.
2. Go to Request Access and enter an IP, IP range or ASN you own.
3. Pick one of the authorization addresses SNDS finds, such as postmaster@ or abuse@ your domain from reverse DNS, or a contact in the RDAP record.
4. Click the link in the authorization email.

The FAQ says Microsoft "cannot process manual requests for access" and can't adjust authorizations by hand. If no usable address is found, try a smaller range, fix your reverse DNS or RDAP contacts, or have the person who receives the authorization email complete it. Access lasts 10 months, after which you must reattest.

Reading SNDS data

Data for each day is aggregated after midnight Pacific time and kept for 90 days. Microsoft notes data "may not be present for IPs which sent less than 100 messages on the given day."

For complaint rates, Microsoft says "more than 30% of the IPs sending mail to Outlook.com keep their complaint rate at less than 0.3% and this represents a good bar to shoot for."

The View IP Status page lists IPs with an abnormal status: Blocked, Bot or Junked. It's current as of the last 24 hours, with no history. SNDS only shows data. The FAQ says the SNDS team "is unable to process any requests for deliverability support."

What is JMRP and how do you enroll?

The Junk Mail Reporting Program (JMRP) is Outlook.com's complaint feedback loop. Microsoft says it "returns the full message with headers of any email marked as 'junk' or 'phishing'" by Outlook.com users, and that you "typically start receiving feedback within as little as 72 hours" after enrolling.

1. Sign in to SNDS and open Junk Mail Reporting Program.
2. Enroll your sending IP addresses and the address that should receive reports.
3. Route those reports to a system that suppresses the complaining recipient automatically.
4. Update the enrollment whenever you add sending IPs. Outlook.com's Troubleshooting page reminds senders to update JMRP when moving to new IPs.

JMRP is tied to IPs. The SNDS FAQ notes that if you're behind a shared IP, "you will see all the spam complaints regardless of the sending domain." Our guide to email feedback loops explains how to process these reports and how JMRP compares with Yahoo's and Gmail's programs.

What do Outlook.com bounce codes mean?

Outlook.com publishes its own codes on the Troubleshooting page:

The 421 codes are temporary. Slow down and let your server retry, as with any 421 deferral. The 550 codes are permanent for that attempt. Don't keep resending to the same recipient until you've fixed the cause.

You may also see 550 5.5.0 Requested action not taken: mailbox unavailable for hotmail.com and outlook.com addresses. It usually means the address doesn't exist, similar to 550 5.1.10. If it repeats for the same address, remove it from your list. For blocklist-based rejections, run your IP through the Blacklist Checker.

How do you contact Outlook.com sender support?

If you meet the policies and still have problems, use the support form linked from the Troubleshooting page of the Outlook.com Postmaster site. It requires a Microsoft account. Microsoft says the form is only for the Outlook.com system, "including any address @msn.com, @Outlook.com, @hotmail.com, or @live.com", and that submitting it "does not guarantee that any message you send to users of the Outlook.com services will be delivered." The Policies page adds that if you aren't following the guidelines, "it may not be possible for our support team to assist you."

Before you submit:

1. Fix what you can: authentication, reverse DNS, list hygiene and any compromised machine.
2. Collect the sending IPs, the full bounce text with its code, and the dates and times.
3. Check SNDS for the IP's status, filter result and recent complaint rate.
4. Describe the mail: what it is, how recipients opted in, and your volume.

Outlook.com also says it has no allow list. Its Postmaster site explains: "Outlook.com evaluates all inbound email for malicious content." It does partner with Validity's Sender Certification program, a third-party accreditation.

Next steps

• Confirm SPF, DKIM and aligned DMARC pass with a Deliverability Test to an Outlook.com address.
• If you own your sending IPs, register them in SNDS and enroll them in JMRP this week.
• Suppress every JMRP complainer automatically, and keep your complaint rate well below 0.3%. Our guide to the spam complaint rate covers how to lower it.
• Look up any Outlook.com bounce in the SMTP Error Code Lookup.
• For a wider review, work through the email deliverability checklist.

Browse more guides on running email day to day.