Resource Booking Attendant not Automatically Accepting/Declining Meeting requests

Environment: Exchange 2013 + Outlook 2013

Ive go some conference rooms set up, the problem is they don't auto accept/decline meeting requests even though we have the calendars set to

Set-CalendarProcessing -Identity "Conf Room 1" -AutomateProcessing AutoAccept -DeleteComments $true -AddOrganizerToSubject $true -AllowConflicts $false

When looking at the calendar, users see the meeting, but it is greyed out, and states "This meeting has not been accepted"

I have also logged into the mailbox via Outlook, and set the 'Automatic Accept or Decline' to 'Automatically accept meeting requests and remove canceled meetings' AND 'Automatically decline meeting requests that conflict with an existing appointment or meeting' - Note that I did not check 'Automatically decline recurring meeting requests'.  

This is listed in the 'Resource' mailboxes in Exchange 2013, MailboxType : Private in powershell...

How do we get auto accept/decline working?

Thanks in advance.