Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi! Please first change the password and activate 2 steps verification, after this close all your open sessions:
https://account.live.com/proofs/manage/additional
After this, please review the next link to see if any app that you don’t know has access to your account and delete it:
Finally do this in Outlook using Edge:
Sign in at Outlook.com.
Click the gear (Settings) in the top-right corner.
Search for and open Mail settings.
Go to Rules and check for any rules you didn’t create. If you see suspicious ones (e.g., “forward everything to @.___” or “move everything to Deleted”), delete them right away.
Also check Forwarding and IMAP and make sure there isn’t any address added. If there is and it’s not yours, remove the forwarding.