GetRooms list in Exchange server 2010 sp2 return null

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C#

.NET4

Hi.
like you guessed. I try to get RoomList from EWS.
I use managed Api 1.2

I can get all other objects. But when i use build in method GetRoomLists().
Returned count == 0.

In outlook when i browse address book, i see Rooms ( > 20)


Can someone help me with this issue?

Thanks.