How do I set up Outlook SMTP authentication with 2FA and OAuth2 for GlockApps?

Key findings

• OAuth2 requirement: Microsoft (Outlook/Office 365) is increasingly requiring OAuth2 StartTLS for SMTP authentication, moving away from basic authentication.
• Basic authentication limitations: The ability to use basic authentication, even with app-specific passwords, might be disabled by the Microsoft 365 domain administrator, preventing older apps from connecting.
• Native application support: For successful integration, third-party applications like GlockApps must have native OAuth2 support for Microsoft's SMTP servers.
• App passwords with 2FA: While similar to Gmail's app password setup, Microsoft's approach for apps that do not support two-step verification is detailed in their support documentation.

Key considerations

• Verify OAuth2 compatibility: Confirm that the specific version of GlockApps or your Mail User Agent (MUA) has built-in support for Microsoft's OAuth2 for SMTP.
• Administrator policies: Check with your Microsoft 365 domain administrator to ensure that basic authentication has not been explicitly disabled for your account, as this can override attempts to use app passwords.
• Microsoft support: If encountering persistent issues, contacting Microsoft support directly can often provide tailored solutions for your specific account and domain configuration. For broader email authentication issues with Outlook, consult our guide on troubleshooting Office 365 DKIM and SPF failures.
• Alternative authentication methods: Explore whether your email service provider (ESP) or application offers alternative, more modern authentication methods compatible with Microsoft's evolving security standards. Review our guide on a simple guide to DMARC, SPF, and DKIM for a foundational understanding of email authentication.

Key opinions

• Seeking guidance: Marketers frequently inquire if Outlook has a similar app password setup to Gmail for enabling 2FA with third-party tools like GlockApps.
• Direct support advised: Many marketers suggest contacting Microsoft support directly as a key step when encountering SMTP authentication errors with Outlook.
• OAuth2 for MUAs: It is often noted that Mail User Agents (MUAs) or applications like GlockApps will require OAuth2 StartTLS with Microsoft for proper functioning.
• Browser cookies requirement: Some users have observed that enabling browser cookies might be necessary for the MUA or application to work with Microsoft's OAuth2, citing Thunderbird as an example of an MUA that works with OAuth2 StartTLS.

Key considerations

• App password viability: Assess if using an app password with 2FA is a viable option for Outlook, considering Microsoft's evolving security policies that favor OAuth2.
• Direct consultation: When encountering persistent authentication issues, scheduling a call with Microsoft support is highly recommended for tailored assistance.
• Application limitations: Be aware that if your domain has basic authentication disabled, applications that do not natively support OAuth2 will not be able to authenticate with Microsoft's SMTP servers. This can impact deliverability and spam placement.
• Technical documentation: Review Microsoft's official documentation on OAuth2 and SMTP authentication to understand the required configuration steps for your application. This is crucial for avoiding issues like your emails being blocked by Outlook.

Key opinions

• Not a deliverability issue: Experts often classify SMTP authentication errors with Outlook as a technical configuration issue rather than a core email deliverability problem.
• Basic auth limitations: The ability to use basic authentication, even with app-specific passwords, can be disabled by a Microsoft 365 domain administrator, making app-specific passwords ineffective.
• OAuth2 necessity: It is stressed that if a domain strictly enforces OAuth2, then any application connecting to Microsoft's SMTP servers must natively support OAuth2 for authentication.
• No credential hijacking: Experts clarify that OAuth2 does not operate by 'hijacking' another application's credentials; it is a secure, delegated authorization process.

Key considerations

• Domain administrator policies: Always confirm with your Microsoft 365 domain administrator whether basic authentication or legacy protocols are enabled or disabled, as this directly impacts your ability to connect. If you're encountering issues, refer to our guide on how to fix common DMARC issues in Microsoft 365.
• Native OAuth2 support: Ensure your sending application, like GlockApps, offers native OAuth2 support for Microsoft SMTP. Without it, connection will fail if basic authentication is restricted. This is particularly important for your email deliverability rates.
• Consult Microsoft resources: For specific setup instructions and troubleshooting, Microsoft's official support and documentation (e.g., Microsoft Learn) are the most reliable sources of information.
• Secure authentication practices: Adopt modern authentication standards like OAuth2 wherever possible to align with major email providers' security requirements and improve overall email security posture.

Key findings

• Azure AD (Entra ID) is central: Microsoft's documentation consistently points to Azure Active Directory (now Microsoft Entra ID) as the primary platform for managing app registrations and configurations for OAuth2 authentication.
• Specific OAuth2 flow: The Microsoft identity platform supports the OAuth 2.0 authorization code flow, which is the recommended method for applications interacting with Microsoft services securely.
• Application setup steps: Setting up OAuth2 for SMTP requires specific steps including creating an App Registration, adding Client Secrets, and configuring API Permissions within the Azure portal.
• App passwords as a fallback: Microsoft provides information on using app passwords for applications that do not support two-step verification, serving as a legacy method for certain scenarios.

Key considerations

• Follow official guides: Adhere strictly to Microsoft's official documentation for setting up OAuth2 for Office 365 SMTP, as configurations can be intricate and specific to the platform. For general guidelines, consider how to comply with Outlook's new sender requirements.
• Permissions and scopes: Ensure that the correct API permissions are granted to your application registration in Azure AD to allow it to send mail on behalf of users, particularly for delegated or application permissions.
• Deprecation of basic auth: Be aware that Microsoft is actively deprecating basic authentication in favor of modern methods. Plan for migration to OAuth2 to avoid future disruptions in email sending. This is a critical factor for email deliverability issues.
• GlockApps compatibility: Verify with GlockApps's documentation or support if their platform natively supports Microsoft's OAuth2 for SMTP, or if they offer specific workarounds for accounts with basic authentication disabled.