Basic Authentication Deprecation in Exchange Online – September 2022 Update

George_Guo To be fair, it is not really news that Basic Auth will be disabled. If you must continue to use pop, and given that https://learn.microsoft.com/en-us/exchange/troubleshoot/administration/cannot-connect-mailbox-pop-imap-outlook, you might want to explore using a different email client that supports pop with Modern Auth, e.g. Thunderbird (example config instructions at https://kb.uconn.edu/space/IKB/26063831538). Thunderbird might be used by the "IT guy" and then you might want to focus attention on some changes to how your staff work with shared mailboxes. For example, there should also be an Outlook client setting that configures how mails are marked as read or not. E.g.,