Getting an error message similar to the screen shot below?
As of June 2018 Microsoft does not yet support add-ins for shared mailboxes. Since CloudExtend Outlook is a Microsoft add-in you will receive this message when attempting to use CloudExtend from a shared mailbox.
Microsoft has advised that they are investigating supporting this for all users. Once they do CloudExtend Outlook will also support it.
Meanwhile, we have tested this extensively and found that we can use CloudExtend Outlook on Mac Outlook 2016 (desktop only). Since Microsoft does not yet officially support shared mailboxes this may stop working at any time so we encourage you to proceed with caution.