n8n Cron Job Triggers Unauthorized Error for OneDrive Excel File

Based on the error and your setup details, here are some steps to troubleshoot and resolve the issue:

1. Verify OAuth2 Configuration

Ensure that your Microsoft Azure app registration is set up correctly for accessing Excel files on OneDrive. Specifically:

• Redirect URI: Confirm that the OAuth Callback URL from your n8n credential is correctly pasted into your Azure app's Redirect URI.
• Client ID and Secret: Double-check that your n8n credentials use the exact Application (client) ID and generated client secret from Azure.
• Scopes: Make sure your OAuth2 configuration in n8n includes the necessary scopes to access OneDrive files and Excel. Often, this means adding scopes such as Files.Read, Files.ReadWrite, and possibly offline_access if you want the token to refresh automatically.

2. Token Refresh Behavior in Headless Mode

Since you mentioned the job may run fine when an n8n tab is open but fails when the device is closed, the issue could be that the token is being refreshed interactively. In headless (scheduled) executions, n8n must rely on a valid stored token or refresh token:

• Re-authorize Your Credentials: Try re-authorizing your Microsoft credentials in n8n. This ensures that all required permissions and refresh tokens are stored so that headless executions don’t depend on an open browser session.
• Check Token Expiration: Verify that the token hasn’t expired and that n8n is configured to automatically use the refresh token. A misconfiguration might be resulting in an expired token when running the cron schedule.

3. Verify File Access Permissions

The error indicates that the file is not permitted to be opened "in the browser." This can be caused by file-specific sharing settings in OneDrive:

• FileSharing Settings: Make sure the Excel file is either shared with the account used for authentication or that the account has the required access permissions.
• Service Account vs. Delegated Permissions: If you’re using delegated permissions (the file being accessed as a specific user), ensure that the account has direct access. Alternatively, consider setting up a service account with the appropriate permissions if sharing issues persist.

4. Follow Documentation Guidance

The Microsoft credentials documentation in n8n covers these areas in detail. You might want to re-visit the following sections for guidance:

• Using OAuth2 – Instructions on registering an application and generating a client secret.
• Service-specific settings – For Microsoft Excel (and OneDrive), double-check you’ve added any extra required settings (such as the required scopes).

Summary

• Re-authorize your OAuth2 credentials to ensure that the refresh token and required permissions (scopes) are stored.
• Confirm that your Azure app registration is set up correctly, including the correct redirect URI.
• Verify that the file’s sharing settings in OneDrive grant access to the account used by your n8n workflow.
• Ensure that your configuration supports headless execution (i.e., no reliance on an open browser session for token refresh).

Applying these steps should help resolve the authorization error during your scheduled job runs. Let me know if you need more details on any of these steps!