Hi Jiri,
"Account Display Name" was introduced to enable support of multiple email accounts. Please note that Email Account is a completely different concept than Shared Mailbox. The easiest way to tell if you have a Shared Mailbox or Email Account is to open Outlook and then go File -> Account Settings -> Account Settings... If you are able to find the mail box under Email tab, it is an Email Account. Otherwise, it is a Shared Mailbox.
To quote Microsoft on Shared Mailbox,
"A shared mailbox is a type of user mailbox that doesn't have its own user name and password. As a result, users can't log into them directly. To access a shared mailbox, users must first be granted Send As or Full Access permissions to the mailbox. Once that's done, users sign into their own mailboxes and then access the shared mailbox by adding it to their Outlook profile..."
You should only use either "Account Display Name" or "Shared Mailbox" at anytime on those actions. "Account Display Name" should be specified when accessing one of the email accounts while "Shared Mailbox" should be specified when accessing shared mailbox only. Usually you may use the display name you see in Outlook as the value to those parameters.
Hope this helps.
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Bruce Liu
Senior Product Consultant, Professional Services
Blue Prism
Australia/Sydney
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