Outlook.com and Hotmail SMTP settings: smtp-mail.outlook.com, port 587
SMTP settings for Outlook.com, Hotmail and Live accounts: smtp-mail.outlook.com, port 587 STARTTLS. Why basic-auth apps stopped working, what still works, sending limits and error fixes.
Outlook.com / Hotmail outgoing mail server:
smtp-mail.outlook.com, port <code>587</code> (STARTTLS), username = your full address, password = the account password with modern authentication.
Outlook.com / Hotmail SMTP settings at a glance
| Outgoing (SMTP) host | smtp-mail.outlook.com (smtp.office365.com also accepts personal accounts) |
|---|---|
| Ports & encryption |
587 — STARTTLS <em>(the only supported submission port)</em> |
| Username | your full address, e.g. you@outlook.com / @hotmail.com / @live.com |
| Password | the account password with modern authentication (OAuth 2.0); app passwords where the client supports them |
| Authentication | Microsoft has been retiring Basic Authentication for personal Outlook.com accounts (announced for September 2024). Apps that only know username + password over SMTP increasingly get "535 5.7.139 Authentication unsuccessful". Mail clients that support modern auth (Outlook, Apple Mail, Thunderbird) keep working; scripts, printers and CMS plugins usually do not, which is the main reason people move website mail to a relay. |
How to set up Outlook.com / Hotmail SMTP
- Open Outlook.com → Settings → Mail → Sync email; make sure "Let devices and apps use POP/SMTP" is on.
- If you use two-step verification, create an app password at account.microsoft.com → Security → Advanced security options → App passwords.
- In the app: host smtp-mail.outlook.com, port 587, STARTTLS, username = full address, password = account/app password.
- If you get 535 5.7.139, the app is using basic auth that Microsoft has disabled for your account — switch to an OAuth-capable client or a relay.
Sending limits
- About 300 recipients per day and 100 recipients per message for a personal account; new accounts are lower until they build history.
- From must be the account or a verified alias.
Things that catch people out
- Port 465 is not offered; port 25 is not accepted for submission.
- The daily cap is per account and Microsoft does not publish the exact number; expect a 24-hour block after a burst.
Common Outlook.com / Hotmail SMTP errors
| Server reply | Meaning | Fix |
|---|---|---|
535 5.7.139 Authentication unsuccessful, basic authentication is disabled | Password auth is off for the account. | Use an OAuth-capable client, or send application mail via a relay that accepts SMTP AUTH. |
550 5.3.4 Message size exceeds fixed maximum message size | Attachment too large (limit ~20–25 MB). | Shrink the message or share a link. |
554 5.2.0 STOREDRV.Submission.Exception:OutboundSpamException | Outlook flagged the account for spam-like sending. | Stop bulk sending from a personal mailbox. |
More codes: 535 authentication failed, 550 relay denied, 554 rejected as spam, connection timed out — or all SMTP error codes.
When Outlook.com / Hotmail is not enough for your app
When a provider caps you or blocks a port, point the same app at QueenSMTP instead: host smtp.queensmtp.com, port 587 (STARTTLS) or 465 (SSL), your SMTP username and password from the dashboard. $5/year plus $0.10 per 1,000 emails, 100 free a day to test.
Get SMTP credentials — free to test Test Outlook.com / Hotmail nowRelated settings
Outlook.com / Hotmail SMTP — questions
Hotmail, Live and Outlook.com are the same service: host smtp-mail.outlook.com, port 587, STARTTLS, username = your full address.
Microsoft disabled basic (password) authentication for personal accounts. Apps must use modern authentication; those that cannot need a different SMTP provider.
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