So at the moment, users on Mac aren't able to use our add-in with their shared mailboxes.

Search the mailbox you wish to add to Outlook then click Add. In the next window, click Delegates then + button. How to add or remove email accounts Reduce the noise Keep your inbox and attention focused by blocking emails from specific people or groups. To add a shared mailbox to Outlook, follow these steps: Open Outlook, select the Tools menu then click Account. We use the shared properties target email address to then get the graph user id for the conversion of the itemId to a REST ID, which is failing because the email address is undefined. When you add your email accounts (such as iCloud, Exchange, school or work) to Mail, you get all your emails in one place without signing in to any websites. Open an add-in pane and try to call .getSharedPropertiesAsync().Select a mail item from the delegate/shared mailbox.Sign in to Outlook for Mac with a user that has delegate or shared mailbox access.Here's the same user accessing the same shared mailbox from Safari OWA and the call succeeding: Here's another just to show the shared mailbox context: See the screenshot above, but even when the api set should be supported and in a shared or delegate mailbox the getSharedPropertiesAsync call just returns undefined. The () will return the shared properties, and not undefined. That version number is from the week following the release, so it's likely what we tested on. I believe that was Outlook 16.45 (20121303) but I can't confirm because app insights doesn't quite go back to the testing phase. We released an update to our add-in towards the end of January this year and during testing it worked fine. The isApiSetSupported('Mailbox', '1.8') is returning true, the selected mailbox item is in a shared mailbox, but in my add-in and in the console only see the following: I've noticed recently that the call to () is undefined when in Outlook for Mac 16.48 and 16.49.

Mac add shared mailbox