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  • SMARTGAMER2026's avatar
    SMARTGAMER2026
    Copper Contributor
    May 23, 2026

    Hi! Yes, this is absolutely possible.

     

    You can use an Office 365 Business Standard license to connect to your existing Outlook 2021 LTSC application. Outlook LTSC is fully compatible with Microsoft 365 Exchange Online mailboxes.

     

    How to set it up:

     

    When you open Outlook 2021 LTSC, go to File > Add Account.

     

    Enter the email address associated with your Microsoft 365 Business Standard subscription.

     

    Outlook will use Modern Authentication (OAuth) to connect. It will prompt you for your Microsoft 365 login credentials.

     

    Once authenticated, your mailbox will sync automatically.

     

    Note: Ensure your Outlook 2021 LTSC is fully updated via Windows Update to ensure it has the latest compatibility patches for Microsoft 365's modern authentication protocols.