MS.SHAREPOINT.1.2v1 - External sharing for OneDrive SHALL be limited to "Existing guests" or "Only people in your organization".
Information
Sharing files outside the organization via OneDrive increases the risk of unauthorized access. By limiting external sharing, administrators decrease the risk of unauthorized access to information.
Solution
1. Sign in to the SharePoint admin center. 2. Select Policies \> Sharing. 3. Adjust external sharing slider for OneDrive to Existing Guests or Only people in your organization. 4. Select Save.