Frequently Asked Question
Microsoft 365 IMAP4 & SMTP
Last Updated 3 hours ago
For Microsoft 365 mailboxes using IMAP and SMTP, use the following settings.
Microsoft 365 IMAP4 and SMTP settings
| Setting | Value |
|---|---|
| Incoming mail server (IMAP) | outlook.office365.com |
| IMAP port | 993 |
| IMAP encryption | SSL/TLS |
| Outgoing mail server (SMTP) | smtp.office365.com |
| SMTP port | 587 |
| SMTP encryption | STARTTLS |
| Username | Full email address |
| Password | Mailbox password |
Authentication details
- The username should be the full Microsoft 365 email address.
- The password should be the mailbox password.
- SMTP authentication should be enabled.
- The outgoing server should use the same login details as the incoming server.
Important notes
- Microsoft 365 does not support standard unencrypted IMAP or SMTP settings for normal use.
- For IMAP, use
SSL/TLSon port993. - For SMTP submission, use
STARTTLSon port587. - Port
25is generally not used for end-user mail client submission and may be blocked or unsuitable. - In some environments, Microsoft may require modern authentication rather than basic username/password authentication. Older mail clients may therefore fail even if the server names and ports are correct.
Summary
Use the following values in the mail client:
- IMAP server:
outlook.office365.com - IMAP port:
993 - IMAP security:
SSL/TLS - SMTP server:
smtp.office365.com - SMTP port:
587 - SMTP security:
STARTTLS - Username: full email address
- Password: mailbox password
This is correct at the time of authoring, but may change over time. Whilst we endeavour to keep documentation updated, if this doesn't work please check with official Microsoft Documentation.
