[feat] Deny NEW outlook users, Microsoft Cloud

You know that New Outlook is not an Email Client but a service on Microsoft Cloud that uses the imap credentials in Outlook to check the mailbox from Microsoft servers.

I would like to block users of my domain configuring 'New Outlook' (usually by mistake) on their PC because i don't want private data going to the Microsoft's Cloud.

Would it be possible to block IPs/hostnames of Microsoft servers to login/authenticate (on imap, pop, smtp)?
An imap/pop login log (also a synthetic log of last unique IPs, per user) would be useful and sufficient.

No files, tests, or entry points are identified in the issue. Start by locating the IMAP, POP, and SMTP authentication paths and the existing login logging, then determine whether blocking Microsoft endpoints or recording unique client IPs fits the current architecture. Done should include a clear, tested behavior for the requested protection or logging.

Written by the indexing model from the issue text.