Email server settings
Microsoft 365 SMTP, IMAP & POP3 settings
Use these settings to add your Microsoft 365 account (office365.com, onmicrosoft.com, mail.protection.outlook.com) to Outlook, Apple Mail, Thunderbird, your phone or any app that sends email over SMTP.
Incoming mail
IMAP
- Server
- outlook.office365.com
- Port
- 993
- Security
- SSL/TLS
- User name
- full email address
- Authentication
- OAuth 2.0
Incoming mail
POP3
- Server
- outlook.office365.com
- Port
- 995
- Security
- SSL/TLS
- User name
- full email address
- Authentication
- OAuth 2.0
Outgoing mail
SMTP
- Server
- smtp.office365.com
- Port
- 587
- Security
- STARTTLS
- User name
- full email address
- Authentication
- OAuth 2.0
How to set up Microsoft 365 in a mail app
- Choose add account → manual setup (or "other account") in your mail app.
- Enter your full Microsoft 365 email address and password.
- Pick IMAP for incoming mail and enter the server, port and security from the table above.
- Enter the SMTP server for outgoing mail (smtp.office365.com, port 587) and enable authentication with the same login.
Microsoft 365 supports OAuth 2.0 sign-in. Apps that support it (Thunderbird, Apple Mail, Outlook) open a browser window to sign in, and you do not need to type your password into the mail app.
If the login keeps failing, enable IMAP/POP access in the Microsoft 365 web settings and use an app password if your account uses two-step verification.
Email domains using these settings
office365.com, onmicrosoft.com, mail.protection.outlook.com.
Settings from the Mozilla Thunderbird ISP database (MPL 2.0), which mail clients use for automatic setup.
Microsoft 365 email settings: FAQ
What is the Microsoft 365 SMTP server?
What are the Microsoft 365 IMAP settings?
Should I use IMAP or POP3?
Why does my Microsoft 365 login fail in a mail app?
Email validation API
Validate office365.com addresses before you send
emailvalidation.io checks syntax, MX records and the mailbox over SMTP, flags disposable, role and free addresses and returns a quality score, in one request.
Read the docs100 free validations every month. No credit card required.
GET https://api.emailvalidation.io/v1/info?email=name@office365.com
{
"email": "name@office365.com",
"domain": "office365.com",
"mx_found": true,
"smtp_check": …,
"free": …,
"disposable": false,
"state": "…"
}