Hi @Bruce Plumer ,
Outlook supports OAuth in all current Microsoft 365 subscription SKUs and Outlook 2021 LTSC (any SKU with build 11601.10000 or higher) when connecting directly as Outlook.com. If your Outlook is configured to connect to Outlook.com using POP or IMAP, OAuth is not supported. This means that when Basic authentication is fully deprecated, it will no longer connect.
More detailed information, see: Outlook and other apps are unable to connect to Outlook.com when using Basic authentication
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