Short answer:
The Xink Outlook Add-in only works in the New Outlook for Mac. It is not supported in the classic or legacy versions of Outlook for Mac.
To use the Xink add-in in Outlook for Mac, users must switch to the New Outlook interface (see screenshot below).
Important: The add-in does not work in Outlook for Mac classic UI or Legacy Outlook for Mac.
This limitation is also documented by Microsoft > View Microsoft documentation.
The Xink add-in requires the Outlook API requirement set 1.10, which is only supported in the New Outlook for Mac.
