I managed to add my domain on https://domains.live.com/ and verified MX records. I also created 2 accounts on the domain.

But I am unable to login using the email address and passwords I set up. However, when I try logging in using my @outlook.com email address, I can do so. Emails to my personal email *** Email address is removed for privacy *** are bouncing off giving an error - "Invalid Address, ERROR_CODE :550, ERROR_CODE :Requested action not taken: mailbox unavailable".