Error 'Your authentication token to this content source has expired' in Files Connect OAuth

Follow the steps below to re-authenticate and restore access to the Files Connect External Data Source.

Step 1: Verify App Domain Configuration

Confirm that the App domain of the Office 365 application in Salesforce Setup exactly matches the value specified in the documentation. A mismatch here will cause authentication failures even after re-authentication.

Step 2: Re-authenticate the External System

Delete the expired authentication credentials and re-initiate the OAuth flow.

For Lightning Experience

1. Click your avatar (profile picture) in the top-right corner.
2. Select Settings.
3. Navigate to Authentication Settings for External Systems.
4. Click Del next to the External Data Source showing the error.
5. Initiate the OAuth flow again to re-authenticate.

For Salesforce Classic

1. Click your name in the top-right corner.
2. Select My Settings.
3. Navigate to Personal > Authentication Settings for External Systems.
4. Click Del next to the External Data Source showing the error.
5. Initiate the OAuth flow again to re-authenticate.

For reference, see: Manage Your Files Connect External Data Source Authentication Credentials

Step 3: If the Issue Persists — Recreate the SharePoint App

If re-authentication does not resolve the error:

1. Create a new SharePoint app on the SharePoint side (not in Salesforce Setup).
2. Update or recreate the Authentication Provider in Salesforce Setup to reference the new SharePoint app.
3. Re-validate and sync all External Data Sources in Salesforce that used the old Authentication Provider.
4. If a new Authentication Provider was created, update each affected External Data Source to reference it.

Important: Do not delete any existing External Data Sources in Salesforce. These may be customized for specific SharePoint integration points and may be referenced in other Salesforce objects.

Step 4: Try the Alternate Authentication Method for SharePoint Online

When using the Azure method and additional authentication errors occur, try the alternate method of authentication. SharePoint Online has throttling limitations that can activate when users authenticate against a large site collection. The alternate method can bypass this limitation.
Note: Similar steps apply when Named Principal authentication is used, where the SharePoint admin authenticates on behalf of all users.