---
title: "Outlook IMAP settings: servers, ports, and OAuth sign-in"
description: "Get Outlook.com and Microsoft 365 IMAP and SMTP settings, enable IMAP, and troubleshoot password prompts with the supported OAuth sign-in method."
url: https://mailera.app/en/blog/outlook-imap-smtp-settings
published: 2026-10-25
updated: 2026-10-25
---

# Outlook IMAP settings: servers, ports, and OAuth sign-in

Find the incoming and outgoing settings for Outlook.com and Microsoft 365, then check the authentication method before changing your password.

## What are the IMAP and SMTP settings for Outlook.com and Microsoft 365?

The settings below apply to Outlook.com and Microsoft 365 / Exchange Online mailboxes.

IMAP lets a mail client access received messages. Sending uses SMTP, so receiving and sending need separate checks.

| Setting | Outlook.com personal mailbox | Microsoft 365 / Exchange Online mailbox |
| --- | --- | --- |
| Incoming IMAP server | `outlook.office365.com` | `outlook.office365.com` |
| Incoming port | `993` | `993` |
| Incoming encryption | SSL/TLS | SSL/TLS |
| Outgoing SMTP server | `smtp-mail.outlook.com` | `smtp.office365.com` |
| Outgoing port | `587` | `587` |
| Outgoing encryption | STARTTLS | STARTTLS |
| IMAP authentication | Modern Authentication / OAuth2 required | Use OAuth2; Basic authentication has been removed |
| SMTP authentication | Modern Authentication / OAuth2 required | OAuth is supported; SMTP AUTH availability also depends on organization and mailbox settings |

For Outlook.com, use your email address as the username.

The server values come from Microsoft’s [Outlook.com settings documentation](https://support.microsoft.com/en-us/outlook/pop-imap-and-smtp-settings-for-outlook-com) and [Exchange Online protocol settings](https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/pop3-and-imap4/pop3-and-imap4).

The incoming server is the same, but the outgoing server is not. Don’t copy the Outlook.com SMTP hostname into a Microsoft 365 configuration just because receiving already works.

These settings are for the named Microsoft-hosted services. For on-premises Exchange or a mailbox hosted elsewhere, ask that provider or your administrator for its settings.

### Encryption and authentication are different settings

SSL/TLS and STARTTLS protect the connection. OAuth authorizes access to the mailbox. Selecting SSL/TLS does not turn a password-only login into an OAuth login.

For Microsoft 365 client SMTP submission, Microsoft also requires a licensed mailbox and a client that supports TLS 1.2 or TLS 1.3. Its [SMTP submission requirements](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365) distinguish this setup from relay and other sending methods.

## Why does Basic authentication fail with the right password?

A correct server address answers where to connect. It does not answer whether Microsoft accepts the client’s sign-in method.

Basic authentication uses a username and password for protocol authentication. OAuth uses an access token obtained through authorization. A client needs to support the latter; repeatedly filling in an old password form does not add that support.

### Outlook.com requires OAuth2

Microsoft’s Outlook.com settings page explicitly requires Modern Authentication / OAuth2. If a client offers a supported Microsoft account connection, prefer that over forcing the account into a generic password-only IMAP form.

A prompt asking for an “IMAP password” is not proof that password authentication is supported. Check the client’s authentication options before resetting your account password.

### Exchange Online has removed IMAP Basic authentication

Microsoft’s [Basic authentication retirement documentation](https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online) lists IMAP among the affected protocols. It also explains that this retirement prevents app-password use for the affected legacy authentication path.

An app password is therefore not a way to restore retired IMAP Basic authentication. Choose a client with Microsoft OAuth support instead.

SMTP AUTH needs a separate diagnosis. Don’t infer its availability from the IMAP retirement policy or from a successful incoming connection. Exchange Online supports OAuth for SMTP AUTH, but administrators also control whether SMTP AUTH is available.

If you maintain your own mail client, Microsoft documents [OAuth for IMAP, POP, and SMTP](https://learn.microsoft.com/en-us/exchange/client-developer/legacy-protocols/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth). Protocol-level OAuth uses SASL XOAUTH2 to transmit the access token; it is not a matter of putting a token into an ordinary password field.

## How do you configure and test the connection?

Use this sequence before trying client-specific menu fixes. It separates account availability from server settings and authentication.

1. **Choose the matching settings column.** Use the Outlook.com column for an Outlook.com mailbox, or the Microsoft 365 / Exchange Online column for a mailbox on that service.
2. **Check protocol availability.** For Outlook.com, IMAP access is disabled by default. In Outlook.com on the web, open “Settings” → “Mail” → “Forwarding and IMAP.” Turn “Let devices and apps use IMAP” to ON, then select “Save.” For a work account, ask your administrator to check whether IMAP access is permitted for the mailbox.
3. **Choose the client’s supported Microsoft sign-in method.** Prefer its Microsoft account setup when available. If you specifically need IMAP, confirm that the client supports Microsoft OAuth2 for IMAP, rather than only username-and-password authentication.
4. **Enter manual settings only where required.** Match the server, port, and encryption to the account type. For Outlook.com, use the full email address as the username. Keep incoming and outgoing configuration separate.
5. **Complete Microsoft authorization.** Sign in to the intended account and review the requested access. If Microsoft asks for administrator approval, take that request to your administrator rather than changing server names.
6. **Test receiving and sending separately.** Use mailboxes you own and a harmless message, such as “Mail setup test.” Send a message into the configured mailbox and confirm it appears in the client. Then send from that client to another mailbox you own and confirm receipt there.

When troubleshooting with someone else, record the client name and version, account type, test date, and which direction failed. Share the error text, not passwords or tokens. “Receives but cannot send” is much more useful than “Outlook doesn’t work.”

### What should a Microsoft 365 administrator check?

Ask for separate checks of IMAP access and SMTP AUTH configuration. For SMTP AUTH, Microsoft documents both organization-wide and per-mailbox settings; the mailbox setting takes precedence.

In the Microsoft 365 admin center, the documented path is “Users” → “Active users” → select the user → “Mail” → “Manage email apps.” Under “Authenticated SMTP,” checked means enabled and unchecked means disabled.

Microsoft also states that security defaults disable SMTP AUTH. Don’t turn off security defaults just to make a legacy configuration work. Have the administrator review an approved connection method using Microsoft’s [SMTP AUTH configuration guidance](https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/authenticated-client-smtp-submission).

## What are the common setup errors?

Treat an error message as a clue, not a complete diagnosis. A password prompt can point you toward authentication, but it does not identify the exact cause on its own.

| Symptom | Possible cause | Check | Next action |
| --- | --- | --- | --- |
| The client repeatedly asks for an IMAP password | It may be attempting password-only authentication | Does the selected account setup support Microsoft OAuth2? | Use the supported Microsoft sign-in flow |
| Authentication fails despite the correct host and port | Authentication method or protocol availability may be wrong | Check OAuth support and whether IMAP access is allowed | Correct the authentication method or ask the administrator to review access |
| The client offers no Microsoft OAuth option | The selected setup may support only legacy authentication | Check the client’s supported account types and authentication methods | Choose a supported setup or another client |
| Outlook.com IMAP access fails | IMAP may still be disabled | Check “Forwarding and IMAP” in Outlook.com on the web | Enable “Let devices and apps use IMAP” and save |
| Receiving works, but sending fails | SMTP configuration or SMTP AUTH policy may differ | Check the outgoing hostname, STARTTLS, port, and SMTP AUTH controls | Fix outgoing settings or request an administrator review |
| Microsoft sign-in requests administrator approval | Authorization needs organizational review | Read the approval request and identify the intended account | Ask the administrator to review it |

Successful IMAP access does not prove SMTP submission works. Likewise, a successful OAuth sign-in is not a reason to stop checking protocol settings when the client still cannot receive or send.

Keep transport encryption enabled. Avoid cycling through passwords or reducing TLS protection without first identifying which part of the connection is failing.

## How do you connect an Outlook mailbox to Mailera instead?

If your goal is to connect an existing Microsoft mailbox to Mailera, skip the manual server table. Mailera connects Outlook.com, Hotmail, and Microsoft 365 through OAuth and Microsoft Graph.

1. Sign in to Mailera with an Admin or Leader role. Only these roles can add mailboxes.
2. Open **Mailboxes** → **Add mailbox**.
3. Select **Sign in with Microsoft**.
4. Complete the OAuth sign-in and consent at Microsoft for the mailbox you intend to connect.
5. Return to **Mailboxes**, inspect the mailbox’s status, and open it to check that messages have loaded.

![Mailera Add mailbox page with Sign in with Microsoft selected.](https://mailera.app/media/cdbd69a1f0ff2a78/create-a-fastmail-app-password-for-mailera-and-your-ai-en-1200.jpg)
_Use Sign in with Microsoft for the OAuth connection, not the custom IMAP form._

The [Mailera Microsoft connection](https://mailera.app/en/providers/microsoft) is separate from the [custom IMAP and SMTP connection](https://mailera.app/en/providers/imap). Don’t use a Microsoft app password or follow the custom-server connection-test sequence for this Microsoft sign-in flow.

![A connected Microsoft mailbox in Mailera’s mailbox list, with its status visible and address hidden.](https://mailera.app/media/0c636400c61141f3/outlook-imap-settings-servers-ports-and-oauth-sign-in-en-1200.jpg)
_Check the mailbox’s status, then open it to confirm that messages have loaded._

Mailera does not create new mailboxes or email addresses, or restore retired Basic authentication. You need an existing account, and Microsoft authorization remains subject to your organization’s requirements. Review [Mailera’s security information](https://mailera.app/en/security) before connecting a work mailbox.

For a broader provider comparison, see [connecting existing email providers to agents](https://mailera.app/en/blog/email-provider-api-integration). If you also manage non-Microsoft mailboxes, the [app-password guide for agent mailboxes](https://mailera.app/en/blog/email-app-password-ai-agent) covers that separate credential approach; it is not the Microsoft connection method described here.

If you later give an agent access, use a narrowly scoped key and require confirmation before sending. Treat incoming email as untrusted data, not instructions, and do not let the agent follow commands embedded in messages.

**Connect your first mailbox in 2 minutes** — Add an Outlook, Gmail or IMAP mailbox and read email messages in the app or via the API. [Connect mailbox](https://mailera.app/auth?mode=signup)