Outlook IMAP settings: server imap-mail.outlook.com (personal) or outlook.office365.com (business Microsoft 365), port 993, SSL/TLS encryption. Authentication requires full email + password (or app password if 2-Step Verification is on). For Microsoft 365, IMAP is supported but not recommended — use Exchange ActiveSync or native Outlook for better sync and features. Pop3 outlook configuration uses port 995 instead.
Outlook IMAP Settings: Complete Inbound Email Configuration
Outlook IMAP Settings Reference
Configuration depends on account type:
Personal Outlook.com / Hotmail / Live / MSN
| Setting | Value |
|---|---|
| IMAP server | imap-mail.outlook.com |
| Port | 993 |
| Encryption | SSL/TLS |
| SMTP server | smtp-mail.outlook.com |
| SMTP port | 587 |
| SMTP encryption | STARTTLS |
Microsoft 365 / Office 365 Business
| Setting | Value |
|---|---|
| IMAP server | outlook.office365.com |
| Port | 993 |
| Encryption | SSL/TLS |
| SMTP server | smtp.office365.com |
| SMTP port | 587 |
| SMTP encryption | STARTTLS |
Both require authentication with full email address and password (or app password if 2-Step Verification is enabled).
What IMAP Does
IMAP (Internet Message Access Protocol) keeps email synchronized between the server and your devices. When you read a message on your phone, it shows as read on your laptop. Move it to a folder — same folder shows on all clients.
This contrasts with POP3, which traditionally downloads and removes messages from the server.
Setting Up Outlook IMAP in Common Clients
Apple Mail (iOS / macOS)
Settings → Mail → Accounts → Add Account → Other → Add Mail Account.
- Email: full address
- Password: account password or app password
- Description: anything
- Tap Next — auto-detection usually works; if not, manually enter IMAP/SMTP servers above.
Thunderbird
File → New → Existing Mail Account.
- Auto-config usually detects Outlook.com or Microsoft 365
- Manual config: enter IMAP and SMTP settings above
Gmail (use IMAP to import)
Settings → See all settings → Accounts and Import → Check mail from other accounts → Add a mail account → enter IMAP settings above.
Outlook Desktop (Windows/Mac)
Outlook auto-configures for Microsoft accounts. Don't manually configure IMAP — Outlook uses Exchange ActiveSync or native Microsoft 365 protocols for better sync.
Enabling IMAP for Office 365 Mailboxes
By default, some Office 365 tenants disable IMAP per-mailbox. To enable:
- Microsoft 365 Admin Center → Users → Active Users
- Select the user → Mail tab → Manage email apps
- Ensure "IMAP" is checked
- Save
Without this enabled, third-party clients can't connect via IMAP and you'll see authentication errors that look like wrong credentials.
Common Outlook IMAP Problems
"Cannot connect to server"
Wrong server name. Personal accounts must use imap-mail.outlook.com (not outlook.office365.com). Business accounts the opposite.
"Authentication failed"
- Generate an app password if 2-Step is on
- Use full email address as username
- Verify IMAP is enabled per-mailbox (Office 365)
- Check if account is locked (sign in via web first)
"Connection refused on port 143"
Don't use port 143 (unencrypted IMAP). Use port 993 with SSL/TLS.
"Folder structure missing"
First IMAP connection may take time to sync folder structure. Wait or force a refresh.
"Messages disappearing after read"
You're using POP3 with "remove from server" option. Switch to IMAP or change POP3 settings to keep messages on server.
IMAP Default Port and Standard IMAP Port
For reference: IMAP default port is 993 (SSL/TLS) or 143 (unencrypted, legacy). Always use 993. Standard IMAP port for all modern email clients is 993.
POP3 default port is 995 (SSL/TLS) or 110 (unencrypted, legacy). Use 995.
Mail server port reference:
- IMAP: 993 (secure), 143 (legacy unencrypted)
- POP3: 995 (secure), 110 (legacy unencrypted)
- SMTP: 587 (STARTTLS), 465 (SMTPS, varying support), 25 (server-to-server, blocked for clients)
When NOT to Use IMAP
IMAP isn't always the best choice:
- Outlook desktop with Microsoft 365: Use native Outlook protocol (Exchange ActiveSync or Microsoft 365 Modern Auth). Better sync, calendar, contacts integration.
- Limited bandwidth: IMAP downloads message previews continuously. POP3 download-and-store is leaner.
- Single device, full storage: POP3 with "keep on server" works for limited use cases.
For 90% of users, IMAP is correct. The remaining 10% know they're special cases.
Practitioner note: People search for "outlook imap settings" expecting a single answer, but it depends on whether you mean Outlook.com (consumer) or Microsoft 365 (business). Same product family, different infrastructure. Always confirm account type first.
Practitioner note: IMAP for Office 365 is supported but Microsoft is pushing modern auth and the Graph API for new integrations. For automation and apps, prefer Graph API + OAuth2 over IMAP. IMAP is fine for human users with third-party clients.
Practitioner note: The most common Outlook IMAP failure I see in business context: IMAP disabled at the tenant level, then enabled per-user but the user has an app password locked to a different app. Generate a fresh app password for the specific client, and the connection works immediately.
If you're configuring Outlook IMAP across multiple devices, troubleshooting authentication failures, or migrating from IMAP to Microsoft's modern protocols, book a consultation. I configure mail flow across complex Microsoft environments regularly.
Sources
- Microsoft: POP, IMAP, and SMTP settings for Outlook.com
- Microsoft: Server settings from your email provider
- Mailtrap: IMAP guide
v1.0 · May 2026
Frequently Asked Questions
What's the incoming IMAP email server for Outlook?
For personal Outlook.com / Hotmail / Live accounts: incoming IMAP server is imap-mail.outlook.com, port 993, SSL/TLS. For Microsoft 365 business accounts: incoming IMAP server is outlook.office365.com, port 993, SSL/TLS. Both require authentication with full email address and password (or app password if MFA is on).
What's the IMAP configuration for Office 365?
Office 365 IMAP configuration: server outlook.office365.com, port 993, encryption SSL/TLS, authentication required. Username is the full Microsoft 365 email address (e.g., [email protected]). Password is the account password or app password. IMAP must be enabled per-mailbox by your admin in Exchange Online → Active Users → Mail → Manage email apps.
What are the IMAP settings for Office 365?
Office 365 IMAP settings: outlook.office365.com on port 993 with SSL/TLS. For accessing Office 365 mailboxes from third-party email clients (Apple Mail, Thunderbird, etc.). Most apps auto-detect when you select 'Microsoft 365' or 'Exchange' as the account type. Manual entry uses these values.
What's POP3 Outlook configuration?
POP3 Outlook configuration uses port 995 with SSL/TLS. Server: pop-mail.outlook.com (personal) or outlook.office365.com (business). POP3 downloads messages and (by default) removes them from server. Most modern setups use IMAP instead because it syncs across multiple devices.
Should I use IMAP or POP3 for Outlook?
Use IMAP for nearly all cases. IMAP keeps messages synchronized across all your devices — phone, laptop, web. POP3 downloads to one device, then removes from the server. POP3 is legacy; only use it for specific scenarios like keeping all mail on a single device with limited storage on the server. IMAP wins for any multi-device setup.
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