Why Do Microsoft Entra ID User Credentials Expire After a Few Hours?

Below is an explanation of the issue and some pointers for troubleshooting.

Issue Description

Your workflow uses Microsoft Entra ID credentials (OAuth2), and after a few hours the credential on the users endpoint fails with a 401 error. Although reconnecting the credential resolves the issue temporarily, the token appears to expire overnight. Oddly, the flow targeting groups with the same credential continues to run without problems.

What the 401 Error Indicates

A 401 response with a message such as:

  {"error":"unauthorized_client", "error_description":"Client is unauthorized to retrieve access tokens using this method, or client not authorized for any of the scopes requested."}

means that the access token is no longer valid when the scheduled execution hits. This typically occurs when:

• The access token has naturally expired.
• The OAuth2 token refresh process is not handling the users endpoint properly.
• There could be differences in the API permissions or scopes between endpoints (users vs. groups).

Troubleshooting Steps

1. Verify Scopes and Permissions
   Ensure that the Microsoft Entra ID (OAuth2) credentials have all the necessary scopes for both users and groups endpoints. Sometimes, one endpoint might require an extra permission that isn’t needed for the other.

2. Review Token Expiry and Refresh Settings
   Check whether the token refresh mechanism in the Entra ID credentials is working properly:

   • Confirm that the client secret is correctly generated and configured.
   • Verify that the OAuth2 flow in your n8n credential setup is handling token refresh automatically.

3. Compare API Calls Between Endpoints
   Since the groups endpoint runs without issues, there might be subtle differences in how the endpoints process tokens. Compare the documentation for both endpoints to see if additional configuration is required for the users endpoint.

4. Monitor Token Lifetimes
   It’s helpful to know the lifetime of the OAuth2 access token issued by Microsoft Entra. If the token expires before your scheduled workflow runs, you may need to reauthenticate or trigger a token refresh earlier. Check your app registration on the Microsoft Application Registration Portal to understand token duration and refresh behaviors.

5. Regenerate and Reconnect Credentials
   As a temporary workaround, regenerating the client secret and reconnecting the credentials seems to work for you. This can help confirm that the error is indeed related to token expiry. For a long‑term fix, make sure token rotation is fully supported and properly configured in n8n for your credential setup.

By following the above steps, you should be able to pinpoint whether the issue is due to missing scopes/permissions, an issue in the OAuth2 refresh flow, or another configuration difference between the two endpoints. If the problem persists and only affects the users endpoint, it might be worth reaching out to n8n support for deeper troubleshooting of the Microsoft Entra ID node.