Outlook SMTP Setup: Sending From Outlook Step-by-Step

The Two Outlook SMTP Servers

The name "Outlook" causes confusion because Microsoft uses it for multiple products:

Product	SMTP Server	Use Case
Outlook.com personal (free)	smtp-mail.outlook.com	hotmail.com, outlook.com, live.com addresses
Microsoft 365 / Office 365 (business)	smtp.office365.com	Custom domain on Microsoft 365
Outlook desktop client	(uses account's native protocol)	Doesn't need SMTP config when account is auto-configured

Pick the SMTP server matching your account type, not your client app.

Setup Outlook SMTP (Personal — Outlook.com)

For free personal accounts ([email protected], [email protected], [email protected]):

• SMTP server: smtp-mail.outlook.com
• Port: 587
• Encryption: STARTTLS
• Authentication: yes
• Username: full email address (e.g., [email protected])
• Password: account password or app password (if 2-Step Verification is on)

Daily sending limit: approximately 300 messages.

Setup Outlook SMTP (Business — Microsoft 365)

For business accounts on Microsoft 365 with custom domain ([email protected]):

• SMTP server: smtp.office365.com
• Port: 587
• Encryption: STARTTLS
• Authentication: yes
• Username: full email address (e.g., [email protected])
• Password: account password or app password

Daily limit: 10,000 messages/day, 30/minute per mailbox.

See Office 365 SMTP settings for detailed business configuration including relay and direct send options.

Outlook Com SMTP Setup for Scan-to-Email

Many office multifunction printers and scanners scan documents and email them. Configuring Outlook.com SMTP for scan-to-email:

• Server: smtp-mail.outlook.com
• Port: 587
• TLS/STARTTLS: enabled
• Auth: enabled with the device's dedicated Outlook.com account credentials
• From address: matches the authenticated account

For business scanners on Microsoft 365, use direct send or SMTP relay via connector instead (avoids per-device authentication). See Office 365 SMTP settings.

App Password Setup (Personal Outlook.com)

If 2-Step Verification is enabled:

1. Go to account.microsoft.com/security
2. "Advanced security options"
3. Under "App passwords," create a new one
4. Use the generated 16-character password as the SMTP password

App passwords are required for any third-party SMTP client when 2-Step Verification is on.

App Password Setup (Microsoft 365)

For Microsoft 365 with MFA:

1. Sign in to Microsoft 365 portal
2. "View account" → "Security info"
3. Add method → "App password"
4. Generate and use as SMTP password

Note: Microsoft is phasing out app passwords in favor of OAuth2 for Microsoft 365. Some tenants no longer support app passwords. For new integrations, prefer OAuth2 where supported.

Common Outlook SMTP Setup Problems

"SMTP server timeout"

Usually wrong server name. Personal accounts must use smtp-mail.outlook.com (not smtp.office365.com). Business accounts the opposite.

"Authentication failed"

1. Generate an app password (if 2-Step is on)
2. Use FULL email address as username (not just the prefix)
3. Verify account isn't locked due to suspicious activity (sign in via web first)

"Connection refused"

Wrong port. Use 587 with STARTTLS, not 25 (blocked) or 465 (varying support).

"Cannot send email" from Outlook desktop client

Different issue. Outlook desktop uses Exchange ActiveSync or auto-configured IMAP+SMTP. If sending fails: File → Account Settings → Repair. Don't manually edit SMTP — Outlook desktop manages it.

Outlook SMTP vs Outlook IMAP

For complete configuration:

• Outlook personal IMAP (incoming): imap-mail.outlook.com, port 993, SSL

• Outlook personal POP3 (incoming): pop-mail.outlook.com, port 995, SSL

• Outlook personal SMTP (outgoing): smtp-mail.outlook.com, port 587, STARTTLS

• Office 365 IMAP (incoming): outlook.office365.com, port 993, SSL

• Office 365 POP3 (incoming): outlook.office365.com, port 995, SSL

• Office 365 SMTP (outgoing): smtp.office365.com, port 587, STARTTLS

Practitioner note: The single most common SMTP host for outlook configuration mistake: using the wrong server for the account type. People with personal hotmail.com addresses try smtp.office365.com (doesn't work — wrong server). People with business Microsoft 365 accounts try smtp-mail.outlook.com (doesn't work — wrong server). Match server to account type.

Practitioner note: Microsoft is aggressively deprecating Basic Authentication. New tenants don't allow it; old tenants are being migrated. Build new integrations with OAuth2 from day one. App passwords are a stopgap, not a long-term solution.

Practitioner note: For applications that need to send programmatically, Outlook SMTP (personal or business) is not the right tool. Use a transactional ESP like Postmark or Resend instead. Outlook is for human-sent mail; ESPs are for application-sent mail. The deliverability, monitoring, and scaling differences are huge.

If you're configuring Outlook SMTP for a business workflow — scan-to-email, automated notifications, application sending — and want to verify you're using the right architecture, book a consultation. I'll review your use case and recommend the appropriate setup.

Sources

• Microsoft: POP, IMAP, and SMTP settings for Outlook.com
• Microsoft: How to set up a device to send email
• Mailtrap: Outlook SMTP
• Reply.io: Outlook SMTP settings

---

v1.0 · May 2026