How to configure the Outlook for Mac?
To delete an existing account:
 
  1. Start Outlook
  2. Select Preferences... under the Outlook menu
  3. Select Accounts
  4. Highlight the account to be remove and click the minus button to Delete it
To add your Exchange Online email account:
 
  1. Start Outlook
  2. Select Preferences... under the Outlook menu
  3. Select Accounts
  4. Click the Plus button to add a New Account...
  5. Enter your email address (account@ust.hk) and click Continue
  6. Enter your password to Sign In
  7. Approve the 2FA login request 
  8. Click Done after the account has been added