The Dataloader service is failing to connect to the journal mailbox or the Exchange Store Manager Service cannot process mailboxes and the following error is logged in the DL \ mailbox wlogs.
09:49:17 DEBUG: CExchangeSession::Login - end
09:49:17 DEBUG: WalkDelegateEmailAddresses(session, delegateEmailAddresses) - Get mailbox by delegateConnectString: mailbox=ArchiveMgr_Journal@domain.com;type=user;mode=journal
09:49:17 DEBUG: Failed to OpenAddressBook 1 times, retrying ...
09:49:18 DEBUG: Failed to OpenAddressBook 2 times, retrying ...
09:49:19 ERROR: Session.OpenAddressBook:
09:49:19 [80004005] Unspecified error