Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi,
First things first, this is a user support forum, so there might be delays in response. Rest assured I will help you to the best of my capacity.
The Outlook temporary address starting with BA***** is attached when you have a 3rd party domain name, which is talktalk in your case.
If you go to https://account.live.com/names/manage page, are you able to add an alias?