Block send when web add-ins can't load

This policy setting allows you to control whether Outlook should block sending emails and meeting requests until web add-ins are loaded from Exchange. If you enable this policy setting, Outlook won’t allow emails and meeting requests to be sent until web add-ins are loaded from Exchange. If you disable or don’t configure this policy setting, Outlook will allow emails and meeting requests to be sent even if the latest web add-ins haven’t been loaded from Exchange yet. For more information about when to use this setting, see https://go.microsoft.com/fwlink/p/?linkid=2161562