Office 365 Shared Folders

I am planning to move away from Outlook 2016 to eM Client 7.1. I downloaded and setup my Office 365 account today and synced with no issues.

I am now trying to add the Shared Folders to the client but aside from adding adding Public Folders HowTo - which is displaying an error, I cannot find information on how to add a Office 365 Shared Mailbox to my eM Client.

Following this post: I was able to troubleshoot the problem.

I noticed I was able to add some mailboxes but not others.

The issue was that the mailbox was hidden from the address list.