Microsoft 365 (work or school) IMAP, POP and SMTP settings
The server names, ports and sign-in details you need to add Microsoft 365 (work or school) to Outlook, Apple Mail, Thunderbird or any other email app.
Quick answerIncoming (IMAP):
outlook.office365.com, port 993, SSL/TLS. Outgoing (SMTP): smtp.office365.com, port 587, STARTTLS.Microsoft 365 (work or school) server settings
| Type | Server | Port | Security |
|---|---|---|---|
| IMAP (incoming) | outlook.office365.com | 993 | SSL/TLS |
| POP (incoming) | outlook.office365.com | 995 | SSL/TLS |
| SMTP (outgoing) | smtp.office365.com | 587 | STARTTLS |
Username and password
Username: Your full work or school email address.
Password: Use an app that supports modern sign-in ("Sign in with Microsoft"). Microsoft has turned off Basic (password-only) sign-in for IMAP and POP in Microsoft 365. For SMTP sending, Microsoft has announced that password sign-in will be turned off by default from the end of December 2026; admins can turn it back on for now. A blocked attempt bounces with error 5.7.30.
Good to know
- Your organization's admin can turn IMAP, POP or SMTP sending off for your mailbox. If the settings are right but nothing works, ask IT.
- For printers, scanners and apps that send email, Microsoft recommends other options than SMTP AUTH, such as a connector with SMTP relay. Ask your admin which one your organization uses.
- Some organizations have their own server name. If IT gave you different settings, use theirs.
How to set it up in a mail app
- Open your mail app and choose to add an account. If it offers "Other", "Manual setup" or "Advanced", pick that.
- Choose IMAP (recommended) or POP.
- Enter the incoming and outgoing servers, ports and security from the table above.
- Use the username and password described below.
- Turn on "Outgoing server requires authentication" and use the same username and password.
If it doesn't work
- "Authentication unsuccessful" when sending
- SMTP AUTH is disabled for your mailbox or organization, or the app is using a plain password. Ask IT.
- Sign-in works in Outlook but not in another app
- The other app probably doesn't support modern sign-in. Use an app that does, or ask IT.
Getting a bounce with a code like 550 or 5.7.26 when you send? Look it up in the SMTP error code library.
More help: Microsoft 365 guides.
Questions people ask
- What is the Office 365 SMTP server?
- smtp.office365.com, port 587, with STARTTLS.
- What is the Microsoft 365 IMAP server?
- outlook.office365.com, port 993, with SSL/TLS.
- Why does IMAP work for my colleague but not me?
- Admins can turn IMAP and POP on or off for each mailbox. Ask IT to check yours.