Outlook for Mac does not support “direct booking”. This is an Outlook for Windows only feature that uses the MAPI protocol. Outlook for Mac uses the Exchange Web Services (EWS) protocol for Exchange connectivity.
Non-MAPI clients can book meeting resources such as meeting rooms and projectors using the Resource Booking Attendant, which is built into Exchange Server 2007 and higher. Booking resources using the Resource Booking Attendant is preferable to using Direct Booking because it . . .
Continue Reading: Resource scheduling