How to access Staff M365 account with Outlook 2016 for Mac?
Open Outlook, then on the Outlook menu, click Preferences...
In the Outlook Preferences window, click Accounts.
In the Accounts window, select Exchange or Microsoft 365.
When Accounts window appears, type your M365 Email address (e.g. cctom@cityu.edu.hk) to the E-mail address: text box,
and YourEID@um.cityu.edu.hk (e.g. cctom@um.cityu.edu.hk)
to the User name: text box. (It is @um.cityu.edu.hk,
not @my.cityu.edu.hk). Key in password, clear the Configure automatically check box.
Type outlook.office365.com to the text box Server. Click Add Account to continue.
If the information provided is correct, this account will be set up successfully.