Understanding Why Email Refresh Tokens Expire in Microsoft Accounts

Overview:

White Cup CRM connects with Microsoft for features such as Inbox or Calendar. In authentication systems like Microsoft Identity, refresh tokens are used to maintain a user's session by granting new access tokens when the current ones expire. However, these refresh tokens do not last indefinitely and may expire or be revoked for several reasons. This article outlines the common causes for the expiration or invalidation of email refresh tokens within Microsoft's ecosystem, and how to mitigate or resolve these issues.

Important:

As of January 30, 2021 you cannot configure refresh and session token lifetimes. Microsoft Entra no longer honors refresh and session token configuration in existing policies. New tokens issued after existing tokens have expired are now set to expire at 90 days.

Reasons Why Email Refresh Tokens Can Expire:

1. User Changed Their Password

• Cause: If a user changes their password in their Microsoft account, all associated refresh tokens are immediately revoked to protect the account's security.
• Reference: Microsoft documentation indicates that when a password change occurs, all tokens associated with that user will be invalidated to prevent unauthorized access.
• Impact: This means that any previous refresh tokens will no longer be valid, and the application will need to request a new set of credentials for token renewal.

2. User Revoked Application Permissions

• Cause: If the user revokes the permissions granted to an application via the Microsoft portal, any refresh tokens issued to that application will be invalidated.
• Reference: According to Microsoft’s guidelines, revoking access through the Microsoft Account settings will immediately invalidate the associated refresh token.
• Impact: Applications will lose the ability to renew access tokens without the user granting new permissions.

3. Refresh Token Used from a Different Application

• Cause: Refresh tokens are linked to specific client identifiers (client_id) and secrets (client_secret). If a refresh token generated for one application is later used with a different client_id or client_secret, it will be rejected.
• Reference: Microsoft’s security documentation specifies that tokens are bound to specific applications, and any attempt to use them in a different context is automatically invalidated.
• Impact: An error occurs, and the application must ensure that tokens are used only with the correct credentials.

4. Exceeded the Limit for Active Refresh Tokens

• Cause: Microsoft limits the number of active refresh tokens that can be issued for a given user and application. If too many refresh tokens are generated or used without cleanup, older refresh tokens may be invalidated to ensure system integrity.
• Reference: Microsoft’s security best practices recommend limiting the number of tokens issued to avoid running into issues with token expiration and invalidation.
• Impact: The application must manage token lifecycle efficiently to avoid hitting the refresh token limit, ensuring continued access.

5. Refresh Token Not Used for an Extended Period

• Cause: If a refresh token is generated but the corresponding access token is not used for an extended period, Microsoft may invalidate the refresh token to ensure it is not being used maliciously.
• Reference: Microsoft’s expiration policy indicates that refresh tokens may expire if they are not actively used, especially if access tokens are not being refreshed in a timely manner.
• Impact: If an application does not regularly refresh the access token, it may need to request new credentials to generate a valid refresh token.

6. Renewal Request Error

• Cause: If there is an issue with the token renewal process—such as using incorrect credentials, an expired client_secret, or a malformed refresh_token—the renewal request will fail.
• Reference: Microsoft’s OAuth documentation outlines common errors that can occur during token renewal, such as invalid requests or expired credentials.
• Impact: Applications should ensure that their token renewal process is configured correctly and that credentials are kept up to date to avoid renewal failures.

Best Practices to Prevent Refresh Token Expiration Issues:

1. Monitor Account Changes:
   Be aware of any changes in the user’s Microsoft 365 account settings, such as password changes, and ensure proper handling of refresh token revocation. 

2. Proper Token Lifecycle Management:
   Limit the number of refresh tokens generated and ensure that tokens are used regularly to avoid hitting the expiration limits.

3. Ensure Proper Permissions:
   Regularly check and renew application permissions via the Microsoft portal to maintain valid refresh tokens for use with Office 365.

4. Configure Correct Credentials:
   Ensure that the correct client_id and client_secret are used during token generation and renewal processes to prevent issues with token rejection.

5. Error Handling for Renewal Failures:
   Implement proper error handling for token renewal requests, ensuring that credentials and token formats are correct.

By understanding these common causes of refresh token expiration and following best practices, you can ensure smoother user experiences and prevent disruptions in White Cup CRM with Inbox or Calendar functionalities. 

FAQ: Understanding Refresh Token Expiration in Microsoft Accounts

1. What are refresh tokens, and why do they expire?

Answer:
Refresh tokens are used in authentication systems like Microsoft Identity to maintain a user’s session by renewing access tokens when they expire. They don’t last indefinitely and can expire or be revoked for various reasons to ensure security and system integrity.

2. Why did my refresh token expire after I changed my Microsoft account password?

Answer:
When you change your Microsoft account password, all refresh tokens associated with that O365 account are immediately revoked to protect your account. The application will need to request new credentials for token renewal.

3. How can I prevent refresh token expiration issues?

Answer:
To prevent issues, follow these best practices:

• Monitor Account Changes: Stay aware of any changes in user account settings, like password changes.
• Proper Token Management: Limit the number of tokens generated and ensure they are used regularly.

4. What should I do if my refresh token becomes invalid?

Answer:
If your refresh token becomes invalid, you’ll need to re-authenticate the user to generate a new set of credentials and obtain a new refresh token.

5. Where can I find more information about refresh token expiration policies?

Answer:
You can refer to Microsoft’s official documentation on refresh token expiration for more detailed information about managing tokens in your application.

• Microsoft Authentication Overview
• Refresh tokens in the Microsoft identity platform 
• Revoking Access and Tokens
• What is a Primary Refresh Token?
• Configurable token lifetimes in the Microsoft identity platform (preview)