Exchange Admin Center - Resources disable automatically decline meetings

Hi Dunc_  - The “Automatically decline meetings outside this limit” option translates to the -EnforceSchedulingHorizon attribute in the calendar processing settings. This will hold good only for recurring meetings which go beyond the default 180 days window.

The EnforceSchedulingHorizon parameter controls the behavior of recurring meetings that extend beyond the date specified by the BookingWindowInDays parameter. Valid values are:

• $true: A recurring meeting request is automatically declined if the meetings start on or before the date specified by the BookingWindowInDays parameter, and the meetings extend beyond the specified date. This is the default value.
• $false: A recurring meeting request is automatically accepted if the meetings start on or before the date specified by the BookingWindowInDays parameter, and the meetings extend beyond the specified date. However, the number of meetings is automatically reduced so meetings won't occur after the specified date.

If you want to enable users to book the meeting rooms beyond the 180 days window, you would have to either increase the Booking window or set the -AllRequestOutOfPolicy to TRUE. 

Set-CalendarProcessing <Room> -AllRequestOutOfPolicy $true

Reference: https://learn.microsoft.com/en-us/powershell/module/exchange/set-calendarprocessing?view=exchange-ps

Please note setting the-AllRequestOutOfPolicy to TRUE will mark the meeting as tentative in the room's calendar and would require a resource delegate to approve/decline it.

Hope this helps!

Regards

Dhruva