It’s working for me now. It seems to be a bug (also reported in other forums) for the “Get Outlook Mail Message” activity. Here are the parameters I used to access a shared mailbox and retrieve emails from a particular sender.
Here is the catch: You need to enter the below parameters in the Expression Editor (you now the button with 3 dots . Its a strange but a working theory and like I said its a known bug reported in the other forums.
Here are the fields i used to enter the values in the corresponding ‘Expression Editor’:
1. Input: I entered the shared email box name as shows in my outlook. [Eg. it showed “Test Shared Mailbox”, I entered as-is.
2. MailFolder: My requirement is to search for emails in Inbox folder. Hence, I gave “Inbox” in the MaiFolder parameter.
3. Filter: Ther are many answers provided in various forums. Since my requirement is to drill down the email filter to a particular sender, I provided the sender name as shown in the email. [Eg: I picked up an email from the sender and copied the name (not the email address) to the Filter parameter. Therefore, it goes like "[From]=‘Test Admin’].