When connecting to Exchange with ewsclient and listing folders, there are folders that are used for contact caching.
5/11/2017 3:28:50 PM: [Enumerate (I)] Contacts\Recipient Cache(2) Folder type is Contact
Trying to access the message as a contact fails. According to what I have been able to find, this is a hidden folder. Here is one of the responses to questions about the recipient cache.
From the article WellKnownFolderName enumeration, we can know that the RecipientCache field is applicable for clients that target Exchange Online and versions of Exchange starting with Exchange Server 2013.
This is a new Exchange 2013 folder which is a hidden subfolder of the Contacts folder with a mailbox and its purpose isn't really documented at the moment, but contains like the AutoComplete cache, Addresses for Sent Emails.
Would it be possible for the ewsClient to show the hidden flag (if it even exists) in the list folders collection?
Thanks