unable to address email alias to account

I have been experiencing issues with a foreign hacker trying to use my email address to bypass login credentials and get me to accidently approve sign-in using the authenticator 'number' codes. I want to add an email alias for sign-in to block the attacks, but I am getting a message when I try to add the email alias the there is a 'temporary problem' or 'Microsoft is doing technical maintenance. The issue has persisted for over 24 hours. How can I fix it?